[4.0] 597f4e9 Free topbuild, makes coverity happy

[Tollef Fog Heen]

commit 597f4e909b85a0ff7a988f6646fc3afe76d0e603
Author: Tollef Fog Heen <tfheen at fastly.com>
Date:   Thu Mar 20 20:09:26 2014 +0100

    Free topbuild, makes coverity happy

diff --git a/bin/varnishtest/vtc_main.c b/bin/varnishtest/vtc_main.c
index 3fc2b43..fc3b588 100644
--- a/bin/varnishtest/vtc_main.c
+++ b/bin/varnishtest/vtc_main.c
@@ -378,7 +378,7 @@ i_mode(void)
 	}
 	AN(topbuild);
 	extmacro_def("topbuild", "%s", topbuild);
-
+	free(topbuild);
 	/*
 	 * Build $PATH which can find all programs in the build tree
 	 */