port.tcl: print a hint to run port -v selfupdate if selfupdate fails
port.tcl: print a hint to run port -v selfupdate if selfupdate fails

This gives some debugging advice to the user similar to the message we print
when a port fails to build.
See https://lists.macosforge.org/pipermail/macports-users/2013-April/032407.html

git-svn-id: 620571fa9b4bd0cbce9a0cf901e91ef896adbf27@105533 d073be05-634f-4543-b044-5fe20cf6d1d6

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