freetdm: Its possible to get HW ALARM clear even though we never got the initial alarm.

         Only send out an unblock if block was sent from hw alarm and there are no
         maintenance blocks pending.

libs/freetdm/src/ftmod/ftmod_sangoma_ss7/ftmod_sangoma_ss7_main.c

@@ -1247,6 +1247,25 @@ ftdm_status_t ftdm_sangoma_ss7_process_state_change (ftdm_channel_t * ftdmchan)
 		if (sngss7_test_ckt_blk_flag(sngss7_info, FLAG_GRP_HW_UNBLK_TX)) {
 			SS7_DEBUG_CHAN(ftdmchan, "Processing FLAG_GRP_HW_UNBLK_TX flag %s\n", "");
 
+			if (sngss7_clear_ckt_blk_flag(sngss7_info, FLAG_GRP_HW_BLOCK_TX) &&
+			     sngss7_clear_ckt_blk_flag(sngss7_info, FLAG_GRP_HW_BLOCK_TX_DN)) {
+				
+				/* Block was sent out we must send an unblock */
+				/* Do not send an unblock if we also have Management block
+				   enabled */
+   			
+				if (!sngss7_test_ckt_blk_flag(sngss7_info, ( FLAG_CKT_MN_BLOCK_TX
+   								   | FLAG_CKT_MN_BLOCK_TX
+   								   | FLAG_GRP_MN_BLOCK_TX
+   								   | FLAG_GRP_MN_BLOCK_TX_DN
+   								   )
+   						      )
+				) {
+					ft_to_sngss7_ubl(ftdmchan);
+				}	
+				
+			}
+
 			sngss7_clear_ckt_blk_flag(sngss7_info, FLAG_GRP_HW_BLOCK_TX);
 			sngss7_clear_ckt_blk_flag(sngss7_info, FLAG_GRP_HW_BLOCK_TX_DN);
 			sngss7_clear_ckt_blk_flag(sngss7_info, FLAG_GRP_HW_UNBLK_TX);