BUG: PNL validation exception

[cxallan]

java.lang.RuntimeException: omero.ValidationException
    serverStackTrace = "ome.conditions.ValidationException: not-null property references a null or transient value: ome.model.acquisition.Microscope.type; nested exception is org.hibernate.PropertyValueException: not-null property references a null or transient value: ome.model.acquisition.Microscope.type
                        	at org.springframework.orm.hibernate3.SessionFactoryUtils.convertHibernateAccessException(SessionFactoryUtils.java:648)
                        	at org.springframework.orm.hibernate3.HibernateAccessor.convertHibernateAccessException(HibernateAccessor.java:412)
                        	at org.springframework.orm.hibernate3.HibernateInterceptor.invoke(HibernateInterceptor.java:117)
                        	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
                        	at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:108)
                        	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
                        	at ome.tools.hibernate.ProxyCleanupFilter$Interceptor.invoke(ProxyCleanupFilter.java:231)
                        	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
                        	at ome.services.util.ServiceHandler.invoke(ServiceHandler.java:111)
                        	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
                        	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
                        	at $Proxy56.doWork(Unknown Source)
                        	at ome.services.util.Executor$Impl.execute(Executor.java:339)
                        	at ome.services.throttling.Adapter.run(Adapter.java:51)
                        	at ome.services.throttling.InThreadThrottlingStrategy.runnableCall(InThreadThrottlingStrategy.java:89)
                        	at ome.services.blitz.impl.AbstractAmdServant.runnableCall(AbstractAmdServant.java:150)
                        	at ome.services.blitz.impl.MetadataStoreI.saveToDB_async(MetadataStoreI.java:167)
                        	at omero.api._MetadataStoreTie.saveToDB_async(_MetadataStoreTie.java:85)
                        	at omero.api._MetadataStoreDisp.___saveToDB(_MetadataStoreDisp.java:211)
                        	at omero.api._MetadataStoreDisp.__dispatch(_MetadataStoreDisp.java:333)
                        	at IceInternal.Incoming.invoke(Incoming.java:159)
                        	at Ice.ConnectionI.invokeAll(ConnectionI.java:2037)
                        	at Ice.ConnectionI.message(ConnectionI.java:972)
                        	at IceInternal.ThreadPool.run(ThreadPool.java:577)
                        	at IceInternal.ThreadPool.access$100(ThreadPool.java:12)
                        	at IceInternal.ThreadPool$EventHandlerThread.run(ThreadPool.java:971)
                        "
    serverExceptionClass = "ome.conditions.ValidationException"
    message = "not-null property references a null or transient value: ome.model.acquisition.Microscope.type; nested exception is org.hibernate.PropertyValueException: not-null property references a null or transient value: ome.model.acquisition.Microscope.type"
	at ome.formats.OMEROMetadataStoreClient.saveToDB(OMEROMetadataStoreClient.java:2032)
	at ome.formats.importer.ImportLibrary.importMetadata(ImportLibrary.java:290)
	at ome.formats.importer.ImportLibrary.importImage(ImportLibrary.java:520)
	at ome.formats.importer.ImportLibrary.importCandidates(ImportLibrary.java:223)
	at ome.formats.importer.cli.CommandLineImporter.start(CommandLineImporter.java:128)

[cxallan]

(In [8536]) Fix mis-use of Microscope constructor and handle cases where Microscope objects are populated with an empty or missing MicroscopeType?. (Fixes #3249)