add longestchain to hushd tab

src/mainwindow.ui

@@ -1245,6 +1245,28 @@
               </widget>
              </item>
 
+             <item row="18" column="0">
+              <widget class="QLabel" name="longestchainlabel">
+               <property name="text">
+                <string>Longest Chain</string>
+               </property>
+              </widget>
+             </item>
+             <item row="18" column="2">
+              <widget class="QLabel" name="longestchain">
+               <property name="text">
+                <string>Loading...</string>
+               </property>
+              </widget>
+             </item>
+             <item row="18" column="1">
+              <widget class="QLabel" name="longestchainspacer">
+               <property name="text">
+                <string>|</string>
+               </property>
+              </widget>
+             </item>
+
              <item row="3" column="2">
               <widget class="QLabel" name="solrate">
                <property name="text">

src/rpc.cpp

@@ -585,6 +585,7 @@ void RPC::getInfoThenRefresh(bool force) {
 
         static int lastBlock    = 0;
         int curBlock            = reply["blocks"].get<json::number_integer_t>();
+        int longestchain        = reply["longestchain"].get<json::number_integer_t>();
         int version             = reply["version"].get<json::number_integer_t>();
         int p2pport             = reply["p2pport"].get<json::number_integer_t>();
         int rpcport             = reply["rpcport"].get<json::number_integer_t>();
@@ -600,6 +601,7 @@ void RPC::getInfoThenRefresh(bool force) {
 
         Settings::getInstance()->setZcashdVersion(version);
 
+	ui->longestchain->setText(QString::number(longestchain));
         ui->notarizedhashvalue->setText( ntzhash );
         ui->notarizedtxidvalue->setText( ntztxid );
         ui->lagvalue->setText( QString::number(lag) );