Fix mock==1.1.0 break test_raw_request_chunked

assert_call_count is not support in mock=1.1.0
change assert_call_count statement to 2 steps:
1. get the call count
2. use assertEqual instead

Change-Id: I15cade184403bcbd75f50f1f2074cebc924a96d3
Closes-Bug: #1473309
1 file changed