tryin to unpickle a GNU dbm file doesn't produce the same exception as bsddb....

tryin to unpickle a GNU dbm file doesn't produce the same exception as bsddb. Handle both. Fixes #7013

src/plugins/plugin.py

@@ -250,7 +250,7 @@ class GajimPluginConfig():
             try:
                 self.data = cPickle.load(fd)
                 fd.close()
-            except EOFError:
+            except:
                 fd.close()
                 try:
                     import shelve