Description of problem:
as summary.

Version-Release number of selected component (if applicable):
v3.8.10-1 on devel server.

How reproducible:
100%

Steps to Reproduce:
1.There is a case with estimated_time '11:22:33'.

2.invoke n.TestCase.filter_count( {'case_id__in': [293486], 'estimated_time': '11:22:33'})--->Fault: <Fault 400: ["invalid literal for int() with base 10: '11:22:33'"]>

3.invoke n.TestCase.filter_count( {'case_id__in': [293486], 'estimated_time': '11h22m33s'})--->Fault: <Fault 400: ["invalid literal for int() with base 10: '11h22m33s'"]>


Actual results:


Expected results:
Both step 2 and step 3, system can filter the case.

Additional info: