Fix loop conditional on provisioning workflow volume form

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1506466
The problem described in the BZ was occuring because the
loop that builds the volume provisioning form was checking
the wrong hash keys for its condition and terminating
early.

app/views/miq_request/_prov_dialog_volume_fieldset.html.haml

@@ -17,6 +17,7 @@
 
 .form-horizontal#add-volumes-form
   - while (draw_fields)
+    = options
     #add-volume-fieldset
       - keys.each do |key|
         .form-group
@@ -47,7 +48,7 @@
       %hr
       %div
     - counter += 1
-    - draw_fields = !options[:"volume_name_#{counter}"].blank? && !options[:"volume_size_#{counter}"].blank?
+    - draw_fields = !options[:"name_#{counter}"].blank? && !options[:"size_#{counter}"].blank?
 
 :javascript
   (function(){