"Fix" warning in cc_sunkencity.lua

Thx Diablodoct0r for reporting.
Disable all glEnable/glDisable() calls for GL_CULL_FACE, except one glDisable() during renderer init.

GL_CULL_FACE is effectively always disabled, except for quad strip
rendering, and keeping GL_CULL_FACE disabled there does not seem
to cause any visual artifacts.
Instead, it enhances skeletal animation possibilities
(e.g. flipping bone strips over without it disappearing)