SiteLibraryLoaderUtil: catch NoSuchFileException when scanning for JARs

Without this, a stack trace is emitted to the console log. This causes
a lot of noise particularly when running acceptance tests in Eclipse
because it is emitted on every test.

See [1] for an example of the stack trace.

[1] http://paste.openstack.org/show/182219/

Change-Id: I1624f6a6aa42ae73ae1e97d1cb53d593184567ab
1 file changed