search virtualenvwrapper.sh in PATH

plugins/virtualenvwrapper/virtualenvwrapper.plugin.zsh

-WRAPPER_FOUND=0
-for wrapsource in "/usr/bin/virtualenvwrapper.sh" "/usr/local/bin/virtualenvwrapper.sh" "/usr/local/share/python/virtualenvwrapper.sh" "/etc/bash_completion.d/virtualenvwrapper" ; do
-  if [[ -e $wrapsource ]] ; then
-    WRAPPER_FOUND=1
+wrapsource=`which virtualenvwrapper.sh`
+
+if [[ -f "$wrapsource" ]]; then
   source $wrapsource
 
   if [[ ! $DISABLE_VENV_CD -eq 1 ]]; then
@@ -36,11 +35,6 @@ for wrapsource in "/usr/bin/virtualenvwrapper.sh" "/usr/local/bin/virtualenvwrap
         builtin cd "$@" && workon_cwd
     }
   fi
-
-    break
-  fi
-done
-
-if [ $WRAPPER_FOUND -eq 0 ] ; then
-  print "zsh virtualenvwrapper plugin: Couldn't activate virtualenvwrapper. Please run \`pip install virtualenvwrapper\`."
+else
+  print "zsh virtualenvwrapper plugin: Cannot find virtualenvwrapper.sh. Please install with \`pip install virtualenvwrapper\`."
 fi