Description of problem:
cannot change any advanced settings in the Settings Server → Advanced yaml _file_

Version-Release number of selected component (if applicable):
cfme-5.6.0.9-rc2.1.el7cf.x86_64

How reproducible:
trivial

Steps to Reproduce:
1. navigate to Settings → Configuration → Advanced
2. change _anything_
3. Save

Actual results:
0) "Configuration changes saved"
1) No changes are reflected on document
2) reload page
3) changes are still not reflected on document
4) changes are not made internally, and simply reflected

Expected results:
changes should be saved

Additional info:
this issue blocks as it prevents azure proxy support, hence the severity