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 remote-tracking branch 'nigelgbanks/7.x-fix-for-autocomplete-notice' into lyr-master

Fixes "Notice: Undefined index: \#autocomplete_path in theme_textfield()"
https://github.com/nigelgbanks/islandora_xml_forms/commit/05bc4d06d90b0c795b4f06bf4f0da8989146582d