.gitlab-ci.yml: remove -Werror compilation from scan-build

When we pass '--status-bugs' to the command in combination with '-Werror' in CFLAGS it has the following side effects. In a failed due to Werror build, scan-build fails to find any issues, and marks the run as successfully completed. Hence, combined the -Werror build with address sanitizer, and removed it from clang-analyzer.

Signed-off-by: Nikos Mavrogiannopoulos nmav@redhat.com