fix the regular expression which it would cause the warning messages

This patch should fixed the following warning messages.

/Users/watson/.emacs.d/elpa/motion-mode-20130512.2306/lib/motion/code_converter.rb:88: warning: regexp has invalid interval
/Users/watson/.emacs.d/elpa/motion-mode-20130512.2306/lib/motion/code_converter.rb:88: warning: regexp has `}' without escape
/Users/watson/.emacs.d/elpa/motion-mode-20130512.2306/lib/motion/code_converter.rb:134: warning: regexp has invalid interval
/Users/watson/.emacs.d/elpa/motion-mode-20130512.2306/lib/motion/code_converter.rb:134: warning: regexp has `}' without escape
/Users/watson/.emacs.d/elpa/motion-mode-20130512.2306/lib/motion/code_converter.rb:136: warning: regexp has invalid interval
/Users/watson/.emacs.d/elpa/motion-mode-20130512.2306/lib/motion/code_converter.rb:136: warning: regexp has `}' without escape