Fix autojump sourcing on OSX with Macports (#4801)

* Fix autojump sourcing on OSX with Macports

The last version of autojump available on Macports does not have
anymore different shell scripts (.sh, .zsh, .bash ...) to be sourced
but just one autojump.sh that takes care of that located at
/opt/local/etc/profile.d/autojump.sh

fix # 4625

* Fix bug with macports autojump on OSX.

plugins/autojump/autojump.plugin.zsh

@@ -15,8 +15,8 @@ if [ $commands[autojump] ]; then # check if autojump is installed
     . /etc/profile.d/autojump.sh
   elif [ -f /usr/local/share/autojump/autojump.zsh ]; then # freebsd installation
     . /usr/local/share/autojump/autojump.zsh
-  elif [ -f /opt/local/etc/profile.d/autojump.zsh ]; then # mac os x with ports
-    . /opt/local/etc/profile.d/autojump.zsh
+  elif [ -f /opt/local/etc/profile.d/autojump.sh ]; then # mac os x with ports
+    . /opt/local/etc/profile.d/autojump.sh
   elif [ $commands[brew] -a -f `brew --prefix`/etc/autojump.sh ]; then # mac os x with brew
     . `brew --prefix`/etc/autojump.sh
   fi