Only log error when setting FullScreenSelectedMonitors

We don't want the log to spam every time this parameter is used so only
complain from the parses when the value is changed.

vncviewer/MonitorIndicesParameter.cxx

     if (strlen(value) < 0)
         return false;
 
-    if (!parseIndices(value, &indices)) {
+    if (!parseIndices(value, &indices, true)) {
         vlog.error(_("Invalid configuration specified for %s"), name);
         return false;
     }
 
     int v = strtol(number.c_str(), NULL, 0);
 
-    if (v <= 0) {
-        vlog.error(_("The given monitor index(%s) is too small to be valid"), number.c_str());
+    if (v <= 0)
         return false;
-    }
 
-    if (v > INT_MAX) {
-        vlog.error(_("The given monitor index (%s) is too large to be valid"), number.c_str());
+    if (v > INT_MAX)
         return false;
-    }
 
     indices->insert(v-1);
     return true;
 }
 
-bool MonitorIndicesParameter::parseIndices(const char* value, std::set<int> *indices)
+bool MonitorIndicesParameter::parseIndices(const char* value,
+                                           std::set<int> *indices,
+                                           bool complain)
 {
     char d;
     std::string current;
             current.push_back(d);
         else if (d == ',') {
             if (!parseNumber(current, indices)) {
-                vlog.error(_("Invalid monitor index '%s'"), current.c_str());
+                if (complain)
+                    vlog.error(_("Invalid monitor index '%s'"),
+                               current.c_str());
                 return false;
             }
 
             current.clear();
         } else {
-            vlog.error(_("Unexpected character '%c'"), d);
+            if (complain)
+                vlog.error(_("Unexpected character '%c'"), d);
             return false;
         }
     }
         return true;
 
     // Parsing anything we have left.
-    if (!parseNumber(current, indices))
+    if (!parseNumber(current, indices)) {
+        if (complain)
+            vlog.error(_("Invalid monitor index '%s'"),
+                       current.c_str());
         return false;
+    }
 
     return true;
 }

vncviewer/MonitorIndicesParameter.h

         int fltkIndex;
     } Monitor;
 
-    bool parseIndices(const char* value, std::set<int> *indices);
+    bool parseIndices(const char* value, std::set<int> *indices,
+                      bool complain=false);
     std::vector<MonitorIndicesParameter::Monitor> fetchMonitors();
     static int compare(const void*, const void*);
 };