Fix segfault in certificate verify error path

The X509_STORE_free() function is called in terminate_signature()
already, so avoid the double frees from calling it twice. Also,
X509_LOOKUP_free() is already called by X509_STORE_free(), so it must
not be called here.

Signed-off-by: Patrick McCarty <patrick.mccarty@intel.com>

src/signature.c

@@ -359,12 +359,6 @@ static bool validate_certificate(void)
 error:
 	ERR_print_errors_fp(stderr);
 
-	if (store) {
-		X509_STORE_free(store);
-	}
-	if (lookup) {
-		X509_LOOKUP_free(lookup);
-	}
 	return false;
 }