Force miphoneos-version-min to 5.0

Fixes error on old devices:

dyld: lazy symbol binding failed: Symbol not found: _OSAtomicDecrement32Barrier

  Referenced from: /var/mobile/Applications/###/***.app/***

  Expected in: /usr/lib/libSystem.B.dylib



dyld: Symbol not found: _OSAtomicDecrement32Barrier

  Referenced from: /var/mobile/Applications/###/***.app/***

  Expected in: /usr/lib/libSystem.B.dylib