Increasing timeout for w3af client connection to 20s

w3af-plugin.patch

@@ -2,6 +2,10 @@
 <     proc = subprocess.Popen([cmd])
 ---
 >     proc = subprocess.Popen([cmd, "--no-ssl"])
+51c51
+<     conn = Connection('http://127.0.0.1:5000/')
+---
+>     conn = Connection('http://127.0.0.1:5000/', timeout=20)
 76c76
 <     main()
 \ No newline at end of file