MUImageViewController: fix warning for unused 'img' variable.
MUImageViewController: fix warning for unused 'img' variable.

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