help the user, not prevent them from running kdesvn-build.  Thanks to advice
from Thiago, kdesvn-build will now more accurately detect if it is still
running.

If kdesvn-build is relatively sure it is still running it will prompt the user
to confirm their decision to run concurrently, otherwise it will warn about a
stale lockfile and proceed without further intervention required.

This fixes bug 108968

BUG:108968

svn path=/trunk/KDE/kdesdk/scripts/kdesvn-build; revision=434133