Refactor: libcrmservice: Clarify variables in services__get_lsb_metadata

Use complete words or more readable abbreviations in variable and
constant names.

Use pcmk__s().

Use %zu instead of %llu with a cast to unsigned long long, since we no
longer support pre-C99.

Signed-off-by: Reid Wahl <nrwahl@protonmail.com>