Description of problem:
When prompted for custom base DN, while setting up and LDAP provider, there is no validation for a custom base DN with special chars

Version-Release number of selected component (if applicable):
ovirt-engine-extension-aaa-ldap-1.3.1-1.el7ev.noarch

How reproducible:
100%

Steps to Reproduce:
1. Run ovirt-engine-extension-aaa-ldap-setup and input values for configuring RHDS
2. When prompted for base DN, input custom base DN with special characters:
'!', '^', '&', ')', '=', "'", '"', '<', '>'

Actual results:
setup is successful

Expected results:
setup should FAIL