Fix local metadata synchronization (fixes: #2219)

[obraliar]

Issue: #2219.

This issue is fixed by overloading and using the parse(...) method in MetaDataParser.

The reason was a reset of the local field metaData in DBMSSynchronizer. This caused other instances containing this field not to be up-to-date.

• Change in CHANGELOG.md described
• Manually tested changed features in running JabRef

[koppor]

I merged it, because it is a hotfix. @obraliar Do you think, it is possible to add a testcase for that?

[koppor]

I am testing PostgreSQL using ElephantSQL.com. I am having autosave activated. I restart JabRef. I get following exception:

20:56:15.998 [AWT-EventQueue-0] INFO  net.sf.jabref.logic.importer.OpenDatabase - Opening: C:\Users\koppor\BTSync\Projects\2016-11 - Dagstuhl-Paper\dagstuhl.bib
Nov 20, 2016 8:56:22 PM com.google.common.eventbus.EventBus$LoggingHandler handleException
SEVERE: Exception thrown by subscriber method listen(net.sf.jabref.model.metadata.event.MetaDataChangedEvent) on subscriber net.sf.jabref.shared.DBMSSynchronizer@6695f8f3 when dispatching event: net.sf.jabref.model.metadata.event.MetaDataChangedEvent@6f7e5617
java.lang.NullPointerException
        at net.sf.jabref.shared.PostgreSQLProcessor.notifyClients(PostgreSQLProcessor.java:126)
        at net.sf.jabref.shared.DBMSSynchronizer.listen(DBMSSynchronizer.java:127)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
...
at net.sf.jabref.model.metadata.MetaData.postChange(MetaData.java:202)
        at net.sf.jabref.model.metadata.MetaData.setMode(MetaData.java:143)
        at net.sf.jabref.logic.importer.util.MetaDataParser.parse(MetaDataParser.java:69)
        at net.sf.jabref.shared.DBMSSynchronizer.synchronizeLocalMetaData(DBMSSynchronizer.java:264)
        at net.sf.jabref.shared.DBMSSynchronizer.initializeDatabases(DBMSSynchronizer.java:157)
        at net.sf.jabref.shared.DBMSSynchronizer.openSharedDatabase(DBMSSynchronizer.java:353)
        at net.sf.jabref.shared.DBMSSynchronizer.openSharedDatabase(DBMSSynchronizer.java:358)
        at net.sf.jabref.gui.shared.SharedDatabaseUIManager.openSharedDatabaseFromParserResult(SharedDatabaseUIManager.java:140)
        at net.sf.jabref.JabRefGUI.openWindow(JabRefGUI.java:117)
        at net.sf.jabref.JabRefGUI.<init>(JabRefGUI.java:63)
        at net.sf.jabref.JabRefMain.lambda$start$1(JabRefMain.java:136)

[obraliar]

@koppor oh yes this now also fixed. Thanks for the objection.