Remove unnecessary overrides in gnukfreebsd and gnuknetbsd hints.

Remove unnecessary overrides in gnukfreebsd and gnuknetbsd hints.

hints/gnukfreebsd.sh and hints/gnuknetbsd.sh unconditionally
override Configure's values for ccdlflags and lddlflags, even though
the default Configure guesses should be correct for those systems.
Configure was altered in commit fb2e1bc0638d5a5d7ac552a79a71a996a5d604cc
(Perforce change 23909) to get the correct values, but later commit
46c947e8b9def6de34ac831834a3c290ab266515 (Perforce change 24017) included
these now-outdated hints file changes as part of importing a larger set
of patches from Debian.

This patch removes the unnecessary overrides.  Thanks to Niko Tyni for
digging up the history and supplying the hints/gnukfreebsd.sh patch.