Fix for Notice.

Notice: Undefined index: #autocomplete_path in theme_textfield()
(line 3821 of /Users/peter/reposervice/drupal/includes/form.inc).

As discovered by Peter on google groups:

https://groups.google.com/forum/?fromgroups=#!topic/islandora-dev/9vH6jEXuYtM
Merge pull request #97 from nigelgbanks/7.x-fix-for-autocomplete-notice

Fix for Notice Notice: Undefined index: #autocomplete_path in theme_textfield() (line 3821 of /Users/peter/reposervice/drupal/includes/form.inc).