[RM-644] use bundler only when it was installed
[RM-644] use bundler only when it was installed

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