httpextbin: Add test case for repeatedly configuring elements in bin
httpextbin: Add test case for repeatedly configuring elements in bin

When state is changed to paused in bin, httpextbin configure source
element with parsed uri and filter element which handles given caps.
When state is changed to ready, bin has to release their child elements
in order to configure new child elements.

Change-Id: Ib1465a9d87ca8c9d7aa8fed6b6d76d57572018e4
Reviewed-on: https://gpro.palm.com/29514
Reviewed-by: Jeongseok Kim <0c03ab7a1b32f29697716389c3f9549845834271@lge.com>
Tested-by: Jeongseok Kim <0c03ab7a1b32f29697716389c3f9549845834271@lge.com>

justinjoy/gst-plugins-lp,justinjoy/gst-plugins-lp