libpcp: fix string handling botch in rtime conversion
libpcp: fix string handling botch in rtime conversion

Picked up by QA test 1354.

adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp