webrtc: DTLS setup with Chrome is broken

The following discussion from !2260 (merged) should be addressed:

• @slomo started a discussion: (+1 comment)

  This commit (51821644) breaks DTLS with Chrome:

  0:00:01.315852160 688028 0x7fd8ec001b00 ERROR         dtlsconnection gstdtlsconnection.c:985:handle_error:<GstDtlsConnection@0x7fd8ec008340> Fatal SSL error
  0:00:01.315884488 688028 0x7fd8ec001b00 ERROR         dtlsconnection gstdtlsconnection.c:968:ssl_err_cb:<GstDtlsConnection@0x7fd8ec008340> ssl error: 140568977995520:error:1420B114:SSL routines:ssl_read_internal:uninitialized:../ssl/ssl_lib.c:1735:
  
  0:00:01.315905178 688028 0x7fd8ec001b00 ERROR                dtlsdec gstdtlsdec.c:505:process_buffer:<dtlsdec0> Error processing buffer: Fatal SSL error
  0:00:01.315937574 688028 0x7fd8ec001b00 ERROR                dtlsdec gstdtlsdec.c:620:sink_chain:<dtlsdec0> Failed to process buffer: error