Fix gdbserver connecttion

Remove extra `:` character from empty scheme.
Is needed to fix gdb target remote string from `tcp::<ip>:<port>` to
`tcp:<ip>:<port>`.

Fix baremetal channelString

Change-Id: I169a93599419ee54c182973c2a1f734390f4a035
Reviewed-by: hjk <hjk@qt.io>

src/plugins/baremetal/idebugserverprovider.cpp

@@ -73,6 +73,7 @@ void IDebugServerProvider::setChannel(const QUrl &channel)
 
 void IDebugServerProvider::setChannel(const QString &host, int port)
 {
+    m_channel.setScheme("tcp");
     m_channel.setHost(host);
     m_channel.setPort(port);
 }
@@ -84,10 +85,7 @@ QUrl IDebugServerProvider::channel() const
 
 QString IDebugServerProvider::channelString() const
 {
-    // Just return as "host:port" form.
-    if (m_channel.port() <= 0)
-        return m_channel.host();
-    return m_channel.host() + ':' + QString::number(m_channel.port());
+    return m_channel.toString();
 }
 
 QString IDebugServerProvider::id() const
@@ -336,6 +334,7 @@ void HostWidget::setChannel(const QUrl &channel)
 QUrl HostWidget::channel() const
 {
     QUrl url;
+    url.setScheme("tcp");
     url.setHost(m_hostLineEdit->text());
     url.setPort(m_portSpinBox->value());
     return url;

src/plugins/debugger/gdb/gdbengine.cpp

@@ -4603,7 +4603,7 @@ static QString extractRemoteChannel(const QUrl &url, const QString &pipe)
 
     QString scheme = url.scheme();
     if (scheme.isEmpty())
-        scheme = "tcp:";
+        scheme = "tcp";
 
     // "Fix" the IPv6 case with host names without '['...']'
     QString host = url.host();