REFACTOR: umask(077) --> umask(SSS_DFL_X_UMASK)
There are many calls of umask function with 077 argument. This patch
add new constant SSS_DFL_X_UMASK which stands fot 077. So all
occurences of umask(077) are replaced by constant SSS_DFL_X_UMASK.
Resolves:
https://fedorahosted.org/sssd/ticket/2424
Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>