[cogl/gles] Fix missing symbols in CoglContext
[cogl/gles] Fix missing symbols in CoglContext

Keep the CoglContext in sync between GL and GLES backends. We ought
to find a way to have a generic context, though, and have backend
specific sections.

Fixes bug:

  http://bugzilla.openedhand.com/show_bug.cgi?id=1698

spatulasnout/cogl,gcampax/cogl,gcampax/cogl,djdeath/cogl-android,djdeath/cogl-android,collects/cogl,spatulasnout/cogl,Distrotech/cogl,djdeath/cogl,collects/cogl,djdeath/cogl,Distrotech/cogl,Distrotech/cogl,djdeath/cogl-android,Distrotech/cogl,gcampax/cogl,gcampax/cogl,djdeath/cogl