Avoid referencing file scope context in _context_new()
Avoid referencing file scope context in _context_new()

cogl_context_new() had a mixture of references to the file scope context
variable (_context) and the local (context) variable. This renames the
file scope variable to _cogl_context to catch unnecessary references to
the old name and fixes the code accordingly to reference the local
variable instead.

Reviewed-by: Neil Roberts <822ec91a7ef82248fd36162ca8ac3283eba70848@linux.intel.com>

gcampax/cogl,gcampax/cogl,gcampax/cogl,djdeath/cogl,djdeath/cogl-android,djdeath/cogl-android,djdeath/cogl,djdeath/cogl-android,djdeath/cogl,gcampax/cogl