libpcp: fix log writing code __pmLogPutLabel routine
libpcp: fix log writing code __pmLogPutLabel routine

Fix a mis-allocation of memory in __pmLogPutLabel in
the presence of error codes within labelsets.  Fixes
qa/1109 with labels enabled.

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