change test function includes to use one convention
diff --git a/tests/suites/test_suite_hmac_drbg.function b/tests/suites/test_suite_hmac_drbg.function
index d58c426..56267e0 100644
--- a/tests/suites/test_suite_hmac_drbg.function
+++ b/tests/suites/test_suite_hmac_drbg.function
@@ -1,7 +1,5 @@
 /* BEGIN_HEADER */
-#include <polarssl/hmac_drbg.h>
-
-#include <string.h>
+#include "polarssl/hmac_drbg.h"
 
 typedef struct
 {