Fix resolution of PatchFileN and PatchFileN-md5 in "fink dumpinfo"

Prior to applying this change, "fink dumpinfo" fails to resolve when it hits a PatchFileN, e.g. `fink dumpinfo flac` ends prematurely with

[]
builddependsonly: true
source: mirror:sourceforge:flac/flac-1.2.1.tar.gz
source-md5: 153c8b15a54da428d1f0fadc756c22c7
nosourcedirectory: [undefined]
patchfile: flac.patch
patchfile-md5: 5c41b21888c325ba7d77dcc67e24ac9b
Failed: Unknown field patchfile2