fix a bug in build system where app does not work on iOS5 device
fix a bug in build system where app does not work on iOS5 device

http://hipbyte.myjetbrains.com/youtrack/issue/RM-221

The compile flags for device are missing.
This bug was introduced by 2617e9a3e4a0d99041cad8631ea8b0ad72022ade

katsuyoshi/RubyMotion,jjaffeux/RubyMotion,incbee/RubyMotion,incbee/RubyMotion,beni55/RubyMotion,katsuyoshi/RubyMotion,hboon/RubyMotion,beni55/RubyMotion,jjaffeux/RubyMotion,HipByte/RubyMotion,katsuyoshi/RubyMotion,katsuyoshi/RubyMotion,incbee/RubyMotion,hboon/RubyMotion,HipByte/RubyMotion,beni55/RubyMotion,hboon/RubyMotion,HipByte/RubyMotion,beni55/RubyMotion,jjaffeux/RubyMotion,incbee/RubyMotion,jjaffeux/RubyMotion