add be_svcprop matcher for Solaris

I've added be_svcprop matcher for Solaris.

Usage

    describe 'svc:/network/http:apache22' do 
      it do
        should be_svcprop(
          'httpd/enable_64bit' => 'false',
          'httpd/server_type'  => 'worker',
        )
      end
    end