contrib: change return value of file checking function of check-code.py
This is a part of preparation to apply checking with check-code.py on
code fragments embedded in *.t test scripts.
After this patch, caller of _checkfiledata() can count number of
errors in each code fragments of an actual file.
This will be useful to share --per-file limitation by all embedded
code fragments.
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}