REGTESTS: http_abortonclose: Extend supported versions

This reg-test was backported as far as 2.0. Thus, extend supported versions
accordingly.

This patch must be backported as far as 2.0.

reg-tests/http-messaging/http_abortonclose.vtc

@@ -4,7 +4,7 @@ feature ignore_unknown_macro
 # NOTE : This test may fail if too many vtest are running in parallel because
 #        the port reserved for closed s1 server may be reused by another vtest
 
-feature cmd "$HAPROXY_PROGRAM -cc 'version_atleast(2.5-dev0)'"
+feature cmd "$HAPROXY_PROGRAM -cc 'version_atleast(2.0-dev0)'"
 #REGTEST_TYPE=slow
 
 # b0 : Wait s1 was detected as DOWN to be sure it is stopped