Also fix the unused variable warning that ICC found with Clang

The ICC fix happened on e02cb2b31ab0b171f11d278305d9f532f005bc80. This
now fixes for Clang 3.4:

cached-powers.cc:134:18: warning: unused variable 'kCachedPowersLength' [-Wunused-const-variable]

Change-Id: I876d9d5cf43fb7eb76117d6fdc37265295c360df
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Remove unused static functions from QtQml found by Clang 3.4

qqmlcomponent.cpp:112:23: error: unused function 'buildTypeNameForDebug' [-Werror,-Wunused-function]

Change-Id: I5cc82b20fee8e3f0b61ad59b831723359c8dcda4
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>