system-traffic: Replace wget with curl for negative and ftp tests.

Some distributions, such as Fedora, have replaced wget with wget2, which,
according to its authors, does not have feature parity with wget.

This patch replaces unsupported use cases, such as negative timeouts
and FTP, with `curl`, as these features are not fully
supported/functioning in `wget2`.

Userspace conntrack doesn’t support Extended Passive Mode (EPSV) or
Extended Port Mode (EPRT), both of which are defaults for cURL.
Therefore, we disabled these modes.

Signed-off-by: Eelco Chaudron <echaudro@redhat.com>
Acked-by: Simon Horman <horms@ovn.org>

tests/system-common-macros.at

@@ -266,6 +266,33 @@ m4_define([NETNS_DAEMONIZE],
    ]
 )
 
+# OVS_GET_HTTP([url], [optional_curl_arguments])
+#
+# Do a HTTP get; we are currently using the curl command.
+#
+m4_define([OVS_GET_HTTP],
+    [curl $1 --retry 3 --max-time 1 --retry-connrefused -v $2]
+)
+
+# OVS_GET_FTP([url], [optional_curl_arguments])
+#
+# Do a passive FTP get; we are currently using the curl command.
+#
+m4_define([OVS_GET_FTP],
+    [curl ftp://$1 --retry 3 --max-time 1 --retry-connrefused --disable-epsv
+         -v $2]
+)
+
+# OVS_GET_FTP_ACTIVE([url], [optional_curl_arguments])
+#
+# Do an active FTP get; we are currently using the curl command.
+#
+m4_define([OVS_GET_FTP_ACTIVE],
+    [curl ftp://$1 --retry 3 --max-time 1 --retry-connrefused -v \
+        --ftp-port - --disable-eprt $2
+    ]
+)
+
 # OVS_CHECK_FIREWALL()
 #
 # Check if firewalld is active, skip the test if it is on.