CLI2: Simplify code by using const quote string

The "\'" string is equal to "'", which is already stored in the quote
variable, so we might as well use that.

Thanks to Sebastian Uharek for the review suggestion.

src/CLI2.cpp

@@ -418,7 +418,7 @@ void CLI2::lexArguments ()
     // Process multiple-token arguments.
     else
     {
-      std::string quote = "'";
+      const std::string quote = "'";
 
       // Escape unescaped single quotes
       std::string escaped = "";
@@ -434,7 +434,7 @@ void CLI2::lexArguments ()
         if (!nextEscaped && (character == "\\"))
           nextEscaped = true;
         else {
-          if (character == "\'" && !nextEscaped)
+          if (character == quote && !nextEscaped)
             escaped += "\\";
           nextEscaped = false;
         }