Description of problem:
searching via API with 'os_title=' doesn't work

The docs say it should:
https://access.redhat.com/documentation/en-us/red_hat_satellite/6.9/html/api_guide/index
5.5. Using Extended Searches
$ curl --insecure --user sat_username:sat_password https://satellite.example.com/api/v2/hosts?search=os_title=\"RedHat+7.7\",model=\"PowerEdge+R330\"

Version-Release number of selected component (if applicable):
[root@sat6 ~]# rpm -q satellite
satellite-6.9.6.1-1.el7sat.noarch

How reproducible:
fails on some, works on others

Steps to Reproduce:
$ curl -k -u admin:xxx https://sat6.example.com/api/hosts?search=os_title=\"RedHat+6.10\"
$ 

Actual results:
No output

Additional info:

- This works with hammer:
# hammer host list --search 'os_title = "RedHat 6.10"'
---|------|------------------|------------|--------------|-------------------|---------------|--------------|----------------------
ID | NAME | OPERATING SYSTEM | HOST GROUP | IP           | MAC               | GLOBAL STATUS | CONTENT VIEW | LIFECYCLE ENVIRONMENT
---|------|------------------|------------|--------------|-------------------|---------------|--------------|----------------------
20 | db6a | RedHat 6.10      |            | 10.8.109.168 | 56:6f:9e:11:00:33 | Error         | 6Server      | Dev                  
---|------|------------------|------------|--------------|-------------------|---------------|--------------|----------------------

- It also works if you use match (~) instead of '='
This workaround is in https://access.redhat.com/solutions/2775671

- It also fails with 'v2' in the URL:
$ curl -k -u admin:xxx https://sat6.example.com/api/v2/hosts?search=os_title=\"RedHat+6.10\"
$ 

- It works if you use ASCII codes (note that the trailing double-quote (%22) is not required):
$ curl -k -u admin:xxx https://sat6.example.com/api/hosts?search=os_title=%22RedHat+6.10
{
  "total": 33,
  "subtotal": 1,
...