Internals: Fix GCC8 cppcheck warnings. No functional change.

src/V3Options.cpp

@@ -155,11 +155,11 @@ void V3Options::addParameter(const string& paramline, bool allowPlus) {
     }
 }
 
-bool V3Options::hasParameter(string name) {
+bool V3Options::hasParameter(const string& name) {
     return m_parameters.find(name) != m_parameters.end();
 }
 
-string V3Options::parameter(string name) {
+string V3Options::parameter(const string& name) {
     string value = m_parameters.find(name)->second;
     m_parameters.erase(m_parameters.find(name));
     return value;