Typo in preference name broke key mapping in VNC

The keyboard mapping preference is stored under the name "keymap", but
looked up by "gkeymap", which was always null. The "Map Meta"
preference now works perfectly for me to connect to OS X.
Merge branch 'master' of github.com:nopdotcom/Remmina into antenore_20140714

Typo in preference name broke key mapping in VNC