system-common-macros: Fix conntrack matching.

Seen in GHA recently.
Unit tests are checking conntracks relating to a destination ip address
but the FORMAT_CT macro is not strict enough and would match unrelated
conntracks too.

Example:
148. system-traffic.at:6432: testing conntrack - DNAT with
	additional SNAT ...
[...]
./system-traffic.at:6460: ovs-appctl dpctl/dump-conntrack |
	grep "dst=10.1.1.1" |
	sed -e 's/port=[0-9]*/port=<cleared>/g'
		-e 's/id=[0-9]*/id=<cleared>/g'
		-e 's/state=[0-9_A-Z]*/state=<cleared>/g' | sort | uniq
[...]
@@ -1,2 +1,7 @@
 tcp,orig=(src=10.1.1.1,dst=172.1.1.2,sport=<cleared>,...
+tcp,...,reply=(src=13.107.42.16,dst=10.1.1.10,sport=<cleared>,...
+tcp,...,reply=(src=168.63.129.16,dst=10.1.1.10,sport=<cleared>,...
+tcp,...,reply=(src=20.242.161.191,dst=10.1.1.10,sport=<cleared>,...
+tcp,orig=(src=13.107.42.16,dst=10.1.1.10,sport=<cleared>,...
+tcp,orig=(src=20.242.161.191,dst=10.1.1.10,sport=<cleared>,...

Fixes: 0765951 ("Add support for connection tracking.")
Signed-off-by: David Marchand <[email protected]>

tests/system-common-macros.at

@@ -256,7 +256,7 @@ m4_define([STRIP_MONITOR_CSUM], [grep "csum:" | sed 's/csum:.*/csum: <skip>/'])
 # and limit the output to the rows containing 'ip-addr'.
 #
 m4_define([FORMAT_CT],
-    [[grep "dst=$1" | sed -e 's/port=[0-9]*/port=<cleared>/g' -e 's/id=[0-9]*/id=<cleared>/g' -e 's/state=[0-9_A-Z]*/state=<cleared>/g' | sort | uniq]])
+    [[grep "dst=$1\>" | sed -e 's/port=[0-9]*/port=<cleared>/g' -e 's/id=[0-9]*/id=<cleared>/g' -e 's/state=[0-9_A-Z]*/state=<cleared>/g' | sort | uniq]])
 
 # NETNS_DAEMONIZE([namespace], [command], [pidfile])
 #