Mumble.xcodeproj: update 'Info plist extras' to quote the PLIST variable.
Mumble.xcodeproj: update 'Info plist extras' to quote the PLIST variable.

jinie/mumble-iphoneos,mumble-voip/mumble-iphoneos,HiroshiTakayama/IP-Incom,HiroshiTakayama/IP-Incom,mumble-voip/mumble-iphoneos,mumble-voip/mumble-iphoneos,HiroshiTakayama/IP-Incom,jinie/mumble-iphoneos,HiroshiTakayama/IP-Incom,jinie/mumble-iphoneos