makefile: Raname CC_RUNTIME to RUNTIME
makefile: Raname CC_RUNTIME to RUNTIME

Rename CC_RUNTIME to RUNTIME, it makes more clear
that we want to use a different runtime and not only is related
with a cc-runtime.

Signed-off-by: Jose Carlos Venegas Munoz <821ab150128e889cb3ad9aab6e72689fd9ad26f2@intel.com>

chavafg/tests,clearcontainers/tests,chavafg/tests,devimc/tests,MarioCarrilloA/tests,devimc/tests,clearcontainers/tests,MarioCarrilloA/tests