qemumigparamstest: Drop "unsupported" test case

The aim of "unsupported" test case is to check whether our code
handles 'CommandNotFound' error returned for
'query-migrate-parameters' monitor command. Well, the command is
pretty old and every QEMU that we are dealing with supports it.
Thus this test case is useless. Drop it.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

tests/qemumigparamsdata/unsupported.json

@@ -1,3 +0,0 @@
-{
-
-}

tests/qemumigparamsdata/unsupported.reply

@@ -1,7 +0,0 @@
-{
-  "id": "libvirt-1",
-  "error": {
-    "class": "CommandNotFound",
-    "desc": "The command query-migrate-parameters has not been found"
-  }
-}

tests/qemumigparamsdata/unsupported.xml

@@ -1,4 +0,0 @@
-<test>
-  <migParams>
-  </migParams>
-</test>

tests/qemumigparamstest.c

@@ -219,7 +219,6 @@ mymain(void)
             ret = -1; \
     } while (0)
 
-    DO_TEST("unsupported");
     DO_TEST("empty");
     DO_TEST("basic");
     DO_TEST("tls");