Fixed uninitialized data (current_clip_stack_valid) in context creation
Fixed uninitialized data (current_clip_stack_valid) in context creation

Reviewed-By: Robert Bragg <12e9293ec6b30c7fa8a0926af42807e929c1684f@linux.intel.com>

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