Docker: Handle docker daemon

Avoid calling the docker daemon again and again
if it is currently not running.

Change-Id: I17afa2eca098589bd362149d18e090252ef83f6e
Reviewed-by: hjk <hjk@qt.io>

src/plugins/docker/dockerdevice.h

@@ -107,6 +107,8 @@ public:
 
     void tryCreateLocalFileAccess() const;
     bool hasLocalFileAccess() const;
+    bool isDaemonRunning() const;
+    void resetDaemonState();
     void setMounts(const QStringList &mounts) const;
 
     Utils::FilePath mapToLocalAccess(const Utils::FilePath &filePath) const;