Searching by user with ~ is not properly handled.
Description of problem:
While testing bz 1468388 i noticed that the ~ operator is not handled properly
Version-Release number of selected component (if applicable):
How reproducible: Always
Steps to Reproduce:
1. Create multiple users (eng-user1, eng-user2, bob, sam)
2. Perform some tasks with each of the users.
3. Monitor -> Tasks.
4. Search user ~ eng
Empty search results
Tasks run by users with "eng" anywhere in their user name are returned. See docs  "... If no wildcard is specified, the string is treated as if surrounded by wildcards: rhel7"
The workaround here is to add wildcards to the search like:
user ~ eng-*
This could be an issue for customer who use usernames that contain other information they wish to search on, other then a literal username. For example all service accounts may be prefixed by "serv-servname-".
Apparently when using an alias like 'user' (without the dot), it makes
scoped search pass anything starting with 'user.' into the external
search method. For this reason, we have to do another round of checking
if the key is actually allowed for searching.
The issue doesn't happen with aliases in the dot format (user.login).