Increase test timeout

There are still tests exceeding the 10 second limit,
although they usually take 1 second.
e.g. https://travis-ci.org/civetweb/civetweb/jobs/76692175

test/civetweb_check.h

@@ -41,6 +41,6 @@
 #endif
 
 /* A minimal timeout used for all tests with the "check" framework. */
-#define civetweb_min_test_timeout (10)
+#define civetweb_min_test_timeout (30)
 
 #endif /* TEST_CIVETWEB_CHECK_H_ */