Description of problem:
Filter or search queries done either using the API or webUI for tags with underscores returns no results. This was working fine in 4.1.1*

Version-Release number of selected component (if applicable):


How reproducible:
both my Test and prod environments are showing the same behavior.

Steps to Reproduce:
1. create a tag... "my_awesome_tag_with_UNDERSCORES"
2. tag a VM with my_awesome_tag_with_UNDERSCORES
3. apply a search filter for that tag in the web UI or search with REST API
4. no results

Actual results:
nothing found with web ui. The api returns just the <vm> header

Expected results:
list of vms with tag applied

Additional info:
I first saw this after upgrading from 4.1.1.x to 4.1.2.2-1. 
Hopefully this is the correct team but please reclassify it if not. Its not urgent but very annoying as we have scripted lots of functionality and most of our tags have underscores....