Fix growing LP_PWD
Fix growing LP_PWD

Colors where added again as prefix and suffix of LP_PWD at every
directory change.

joshuarubin/dotfiles,jaesivsm/liquidprompt,dpilone/liquidprompt,pkkolos/liquidprompt,milouse/liquidprompt,dtschan/liquidprompt,nojhan/liquidprompt,joshuarubin/dotfiles,dan-cleinmark/liquidprompt,joshuarubin/dotfiles,BobHood/liquidprompt,joshuarubin/dotfiles,tsbarnes/liquidprompt,alexprengere/liquidprompt,smadhueagle/liquidprompt,laurentbardin/liquidprompt