BTS_Tests: properly release TCH in f_TC_speech_no_rtp()

Otherwise we're getting a DTE when trying to run this function more
than once in a single testcase (e.g. when testing different channel
modes).  This is already done properly in f_TC_speech_rtp().

Change-Id: I290789153bea4b128af29dcf7c52da16b64c4108
Related: SYS#5919, OS#4823
1 file changed