Checksum phase should not delete distfiles if checksum mismatch, because fetch phase will not be re-called if another checksum attempted (which causes file not found errors).
Checksum phase should not delete distfiles if checksum mismatch, because fetch phase will not be re-called if another checksum attempted (which causes file not found errors).

git-svn-id: 620571fa9b4bd0cbce9a0cf901e91ef896adbf27@21967 d073be05-634f-4543-b044-5fe20cf6d1d6

danchr/macports-base,neverpanic/macports-base,danchr/macports-base,macports/macports-base,neverpanic/macports-base,macports/macports-base