don't call cogl_set_default_context in hello.c
don't call cogl_set_default_context in hello.c

Actually calling cogl_set_default_context isn't required because
cogl_context_new implicitly sets the new context to be the default
context. Since we want to eventually get rid of the concept of a default
context we'd rather not pollute the example with the concept.

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