postfix PMDA: be more careful with diagnostics
postfix PMDA: be more careful with diagnostics

When the magic PCP_PERL_FOO variables are set, the code is
generating the pmns and domain.h, so suppress (not so) helpful
messages when this is being done.

aeg-aeg/pcpfans,prasincs/pcp,edwardt/pcp,edwardt/pcp,tjanez/pcp,tjanez/pcp,edwardt/pcp,tjanez/pcp,aeg-aeg/pcpfans,edwardt/pcp,prasincs/pcp,adfernandes/pcp,wuliming/pcp,wuliming/pcp,wuliming/pcp,wuliming/pcp,tjanez/pcp,prasincs/pcp,adfernandes/pcp,tjanez/pcp,prasincs/pcp,prasincs/pcp,adfernandes/pcp,edwardt/pcp,tjanez/pcp,edwardt/pcp,prasincs/pcp,aeg-aeg/pcpfans,adfernandes/pcp,adfernandes/pcp,tjanez/pcp,edwardt/pcp,aeg-aeg/pcpfans,aeg-aeg/pcpfans,adfernandes/pcp,aeg-aeg/pcpfans,adfernandes/pcp,tjanez/pcp,wuliming/pcp,wuliming/pcp,wuliming/pcp,wuliming/pcp,prasincs/pcp,edwardt/pcp,adfernandes/pcp,prasincs/pcp,aeg-aeg/pcpfans,aeg-aeg/pcpfans