Dialog close after pressing ok button

[Ali96kz]

Steps to reproduce:

1. File -> Connect to shared database
2. Enter wrong database password
3. You will see error. When you close or press ok the connect to database dialog will close too.

[tobiasdiez]

Thanks to @harinda05 this should be fixed in the latest development version. Could you please check the build from http://builds.jabref.org/master/. Thanks! Please remember to make a backup of your library before trying-out this version.