Utils: Drop QProcess specific parameters from QtcProcess::finished()

Mid-term plan is to concentrate on use of QtcProcess::result()
instead which is a bit more system-agnostic.

There's quite a bit of potential for downstream cleanup by
re-using QtcProcess::exitMessage() now.

Change-Id: I3806b3f5933d96e64b7cfb18cc6c52823fddcbcd
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/languageclient/languageclientinterface.h

@@ -89,7 +89,7 @@ protected:
 private:
     void readError();
     void readOutput();
-    void onProcessFinished(int exitCode, QProcess::ExitStatus exitStatus);
+    void onProcessFinished();
 };
 
 } // namespace LanguageClient