btrfs-progs: tests: extend mkfs/001 to look for warnings after mkfs

Patch "btrfs-progs: fix false alert on tree block crossing 64K page
boundary" fixes a false alert (warning) when 'btrfs check' is called
right after mkfs.

As we have an extensive mkfs coverage in test mkfs/001, add the check for
the warning there instead of a separate test.

Signed-off-by: David Sterba <dsterba@suse.com>

tests/mkfs-tests/001-basic-profiles/test.sh

@@ -22,6 +22,9 @@ test_get_info()
 test_do_mkfs()
 {
 	run_check $SUDO_HELPER "$TOP/mkfs.btrfs" -f "$@"
+	if run_check_stdout "$TOP/btrfs" check "$dev1" | grep -iq warning; then
+		_fail "warnings found in check output"
+	fi
 }
 
 test_mkfs_single()