Cleanup after p_mcb if L2CA_ConnectReq() failed

If L2CA_ConnectReq() failed, make sure that
we cleanup the lcid cache state after the
affected p_mcb.

Also, extra check and a log message inside function
rfc_check_send_cmd().

Bug: 27334916
Change-Id: Ib2950d12ce456d74355f4bcc0e3c4d87603f8f91