[iOS] crash when mapView is initialized with CGRectZero frame

[RomainQuidet]

Initializing the map view with a zero frame crashes our test app:

2016-01-26 16:16:50.205 Mappy[346:51305] Failed to bind EAGLDrawable: <CAEAGLLayer: 0x145e36d80> to GL_RENDERBUFFER 1
2016-01-26 16:16:50.206 Mappy[346:51305] Failed to make complete framebuffer object 8cd6
2016-01-26 16:16:50.316 Mappy[346:51305] *** Terminating app due to uncaught exception 'CALayerInvalidGeometry', reason: 'CALayer position contains NaN: [nan 23]'

[friedbunny]

Dupe of #1572.

[RomainQuidet]

@friedbunny sorry, searched CGRectZero but did not find it ! Thanks

[friedbunny]

@RomainQuidet No problem, thousands of issues are tough for us to keep track of, too — thanks for the report. 😄