Cosmetics: Reduces the static analysis warnings

test/cppcheck_suppressions.txt

@@ -1,3 +1,5 @@
+unusedFunction:test/regression/regression_test.cc
+unusedFunction:src/utils/string.cc
 unusedFunction:src/transaction.cc
 unusedFunction:src/utils/mbedtls/sha1.c
 unusedFunction:src/utils/mbedtls/md5.c

test/regression/custom_debug_log.cc

@@ -23,10 +23,6 @@
 
 namespace modsecurity_test {
 
-CustomDebugLog *CustomDebugLog::new_instance() {
-    return new CustomDebugLog();
-}
-
 CustomDebugLog::~CustomDebugLog() { }
 
 void CustomDebugLog::write(int level, const std::string& message) {

test/regression/regression.cc

@@ -380,7 +380,9 @@ after_debug_log:
 
 int main(int argc, char **argv) {
     ModSecurityTest<RegressionTest> test;
+#ifndef NO_LOGS
     int test_number = 0;
+#endif
 
 #ifdef WITH_GEOIP
     resources.push_back("geoip");