Bug 460736 - Fix signing in the presence of packed jars

Bug 460736 - Fix signing in the presence of packed jars

The pack200b plugin was executing before pack200a when sign-update-site profile
was active. The solution is to explicitly specify the pack200b to be after
pack200a in the profile.

Change-Id: I8e7a0d528e601dc8ca205b3a71d4fdb676081dfe
Signed-off-by: Marc-Andre Laperle <marc-andre.laperle@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/42709
Reviewed-by: Hudson CI
Reviewed-by: Alexandre Montplaisir <alexmonthy@voxpopuli.im>
Tested-by: Alexandre Montplaisir <alexmonthy@voxpopuli.im>