Merged r5999 from trunk.
scm: catch all exceptions to get scm command version in repository model.
If scm command does not exist, Linux jruby 1.6.2 (ruby-1.8.7-p330) raises java.io.IOException in production environment.
Authored by: tmaruyama 2011-06-03
Parent: [r5999]
Child: [r6001]
