REGTESTS: mark abns_socket as working now

William noticed that the real issue in the abns test was that it was
failing to rebind some listeners, issues which were addressed in the
previous commits (in some cases, the master would even accept traffic
on the worker's socket which was not properly disabled, causing some
of the strange error messages).

The other issue documented in commit 2ea15a080 was the lack of
reliability when the test was run in parallel. This is caused by the
abns socket which uses a hard-coded address, making all tests in
parallel to step onto each others' toes. Since vtest cannot provide
abns sockets, we're instead concatenating the number of the listening
port that vtest allocated for another frontend to the abns path, which
guarantees to make them unique in the system.

The test works fine in all cases now, even with 100 in parallel.

reg-tests/seamless-reload/abns_socket.vtc

@@ -7,6 +7,12 @@
 # file and rename it later.
 # To detect that, check that the first character of the sun_path is 0 for
 # both, and if so, that &sun_path[1] is the same too.
+#
+# Note: there are some tricks here. One of them is that we must not bind the
+# same abns address to multiple processes that may run in parallel. Since
+# vtest cannot provide abns sockets, we're instead concatenating the number
+# of the listening port that vtest allocated for another frontend to the abns
+# path, which guarantees to make them unique in the system.
 
 varnishtest "Seamless reload issue with abns sockets"
 feature ignore_unknown_macro
@@ -14,7 +20,7 @@ feature ignore_unknown_macro
 # abns@ sockets are not available on freebsd
 #EXCLUDE_TARGETS=freebsd,osx,generic
 #REQUIRE_VERSION=1.8
-#REGTEST_TYPE=broken
+#REGTEST_TYPE=bug
 
 haproxy h1 -W -conf {
   global
@@ -31,10 +37,10 @@ haproxy h1 -W -conf {
 
   listen testme
     bind "fd@${testme}"
-    server test_abns_server abns@wpproc1 send-proxy-v2
+    server test_abns_server abns@wpproc1_${h1_testme_port} send-proxy-v2
 
   frontend test_abns
-    bind abns@wpproc1 accept-proxy
+    bind abns@wpproc1_${h1_testme_port} accept-proxy
     http-request deny deny_status 200
 } -start