use websevice to sign Mylyn update site jars

The command line service has been removed. There is a Maven plugin but
it would require larger changes to our build process because it only
signs jars built in the same reactor, whereas we sign our update site at
the end of the build.

Change-Id: I4c0c75806441920c82e2ec4f8b53d6ee6ac72e1c
1 file changed