libpcp/derive.c - resource_leak Original Coverity case #216. http://people.redhat.com/mgoodwin/pcp-cov/1/216derive.c.html#error
libpcp/derive.c - resource_leak
Original Coverity case #216.
http://people.redhat.com/mgoodwin/pcp-cov/1/216derive.c.html#error

Added assert() and explanatory comment to emphasize that P_INIT code is
only executed once per expression.

This commit also fixes issues #221 and #229.

adfernandes/pcp,ryandoyle/pcp_original,ryandoyle/pcp_original,aeg-aeg/pcpfans,adfernandes/pcp,wuliming/pcp,andyvand/cygpcpfans,aeg-aeg/pcpfans,andyvand/cygpcpfans,edwardt/pcp,wuliming/pcp,edwardt/pcp,tjanez/pcp,wuliming/pcp,tjanez/pcp,tjanez/pcp,ryandoyle/pcp_original,mbaldessari/pcp,prasincs/pcp,mbaldessari/pcp,edwardt/pcp,edwardt/pcp,andyvand/cygpcpfans,ryandoyle/pcp_original,prasincs/pcp,andyvand/cygpcpfans,ryandoyle/pcp_original,prasincs/pcp,wuliming/pcp,prasincs/pcp,mbaldessari/pcp,aeg-aeg/pcpfans,edwardt/pcp,andyvand/cygpcpfans,andyvand/cygpcpfans,wuliming/pcp,adfernandes/pcp,aeg-aeg/pcpfans,aeg-aeg/pcpfans,adfernandes/pcp,tjanez/pcp,adfernandes/pcp,adfernandes/pcp,andyvand/cygpcpfans,ryandoyle/pcp_original,tjanez/pcp,aeg-aeg/pcpfans,prasincs/pcp,wuliming/pcp,edwardt/pcp,aeg-aeg/pcpfans,tjanez/pcp,edwardt/pcp,wuliming/pcp,prasincs/pcp,adfernandes/pcp,edwardt/pcp,aeg-aeg/pcpfans,mbaldessari/pcp,prasincs/pcp,adfernandes/pcp,wuliming/pcp,prasincs/pcp,tjanez/pcp,mbaldessari/pcp,ryandoyle/pcp_original,tjanez/pcp,mbaldessari/pcp,andyvand/cygpcpfans,ryandoyle/pcp_original