Fix 'gerrit.sh restart' for relative paths

Trying to restart gerrit using

  gerrit/site/bin/gerrit.sh restart

failed with

  ** ERROR: Cannot locate gerrit.sh

as gerrit.sh internally changed the current directory to the gerrit
site, while still trying to invoke itself using $0. We add a fallback
to also look for $0 in the initial directory.

Change-Id: I8ba9306cf875aa4ec8e5bb8c693360dafdcd16b9
1 file changed