libselinux/utils: fix all the noreturn errors

When building with clang, multiple noreturn issues arise,
for instance:

selabel_partial_match.c:11:1: error: function 'usage' could be declared with attribute 'noreturn' [-Werror,-Wmissing-noreturn]

Fix these.

Signed-off-by: William Roberts <william.c.roberts@intel.com>
14 files changed