Refactor: lrmd: merge two overlapping functions

This removes lrmd/lrmd.c:lsb2uniform_rc() in favor of the public API
include/crm/services.h:services_get_ocf_exitcode() whose semantics
were the same. This favors the lsb2uniform_rc() implementation to
preserve the behavior as closely as possible. The first argument
changes from char* to const char*.