net-mgmt/riemann-c-client: Update to 1.10.1

While here, add LICENSE_FILE and silence portlint warning about order of
USES/USE_*.
Mark as MAKE_JOBS_UNSAFE, random errors with parallel jobs in poudriere
[10.3|11.1] [i386|amd64].

PR: 221440
Submitted by: Dave Cottlehuber <dch@skunkwerks.at> (maintainer)