src/pmdas/linux/proc_scsi.c: small pmdaCache changes
src/pmdas/linux/proc_scsi.c: small pmdaCache changes

- plug small mem leaks on error paths
- add diagnostic warnings when pmdaCache calls fail

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