Plugin Repo onlyif test is broken

[jwhitcraft]

The onlyif test to make sure that the the plugin git repo is updated is broken. This was introduced in #108

==> default: Debug: Exec[rbenv::plugin::update vagrant ruby-build](provider=posix): Executing check 'git remote update; if [ "$(git rev-parse @{0})" = "$(git rev-parse @{u})" ]; then return 0; else return 1; fi ]'
==> default: Debug: Executing 'git remote update; if [ "$(git rev-parse @{0})" = "$(git rev-parse @{u})" ]; then return 0; else return 1; fi ]'
==> default: Debug: /Stage[main]/Devops/Devops::Ruby[devops_ruby]/Rbenv::Compile[1.9.3-p547]/Rbenv::Plugin::Rubybuild[rbenv::rubybuild::vagrant]/Rbenv::Plugin[rbenv::plugin::rubybuild::vagrant]/Exec[rbenv::plugin::update vagrant ruby-build]/onlyif: sh: -c: line 0: syntax error near unexpected token `]'

should be something more like this:

test `git remote update 1> /dev/null; if [ "$(git rev-parse @{0})" = "$(git rev-parse @{u})" ]; then echo 0; else echo 1; fi` -eq 1

[cyrusstoller]

+1