[libcalamares] Reduce copying and warnings

src/libcalamares/utils/NamedEnum.h

@@ -66,7 +66,7 @@ struct NamedEnumTable
     {
         ok = false;
 
-        for ( const auto p : table )
+        for ( const auto& p : table )
             if ( 0 == QString::compare( s, p.first, Qt::CaseInsensitive ) )
             {
                 ok = true;
@@ -87,7 +87,7 @@ struct NamedEnumTable
     {
         ok = false;
 
-        for ( const auto p : table )
+        for ( const auto &p : table )
             if ( s == p.second)
             {
                 ok = true;

src/libcalamares/utils/NamedSuffix.h

@@ -72,7 +72,7 @@ public:
     NamedSuffix( const NamedEnumTable<T>& table, const QString& s )
         : NamedSuffix()
     {
-        for( const auto suffix : table.table )
+        for( const auto& suffix : table.table )
             if ( s.endsWith( suffix.first ) )
             {
                 m_value = s.left( s.length() - suffix.first.length() ).toInt();