Fix meta update in gen exchange (for meta service string updates)

- was assuming all meta changes were related to bit sets
- was returning fail, when successful

git-svn-id: http://svn.code.sf.net/p/retroshare/code/trunk@7397 b45a01b8-16f6-495d-af2f-9b41ad6348cc

libretroshare/src/gxs/rsgenexchange.cc

@@ -1604,7 +1604,7 @@ bool RsGenExchange::processGrpMask(const RsGxsGroupId& grpId, ContentValue &grpC
     {
         if(grpMeta)
             delete grpMeta;
-        return false;
+        return !(grpCv.empty());
     }
 
     ok &= grpCv.getAsInt32(key+GXS_MASK, mask);

libretroshare/src/util/contentvalue.cc

@@ -294,6 +294,10 @@ void ContentValue::clear(){
     clearData();
 }
 
+bool ContentValue::empty() const{
+    return mKvSet.empty();
+}
+
 void ContentValue::clearData(){
 
     std::map<std::string, std::pair<uint32_t, char*> >::iterator

libretroshare/src/util/contentvalue.h

@@ -161,6 +161,11 @@ public:
      */
     void clear();
 
+    /*!
+     * checks if internal kv map is empty
+     */
+    bool empty() const;
+
 private:
 
     /*!