fix a build error when app files is not passed as flat array.
fix a build error when app files is not passed as flat array.

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