ProjectExplorer: create a root path without scheme for host device

Change-Id: I966db6378dca533c73635803fb177d31b2c625ac
Reviewed-by: Jarek Kobus <jaroslaw.kobus@qt.io>

src/libs/utils/filepath.cpp

@@ -1083,6 +1083,7 @@ QString FilePath::calcRelativePath(const QString &absolutePath, const QString &a
 */
 FilePath FilePath::onDevice(const FilePath &deviceTemplate) const
 {
+    isSameDevice(deviceTemplate);
     const bool sameDevice = scheme() == deviceTemplate.scheme() && host() == deviceTemplate.host();
     if (sameDevice)
         return *this;

src/plugins/projectexplorer/devicesupport/desktopdevice.cpp

@@ -150,4 +150,11 @@ Environment DesktopDevice::systemEnvironment() const
     return Environment::systemEnvironment();
 }
 
+FilePath DesktopDevice::rootPath() const
+{
+    if (id() == DESKTOP_DEVICE_ID)
+        return FilePath::fromParts({}, {}, QDir::rootPath());
+    return IDevice::rootPath();
+}
+
 } // namespace ProjectExplorer

src/plugins/projectexplorer/devicesupport/desktopdevice.h

@@ -36,6 +36,8 @@ public:
     Utils::Environment systemEnvironment() const override;
     Utils::FilePath mapToGlobalPath(const Utils::FilePath &pathOnDevice) const override;
 
+    Utils::FilePath rootPath() const override;
+
 protected:
     DesktopDevice();