[nightcolor] Print a debug message upon receiving new location from kded module

Summary:
This can be useful for debugging whether Night Color manager actually
receives new location data from colorcorrectlocationupdater kded module.

CCBUG: 412211

Test Plan:
Run kwin with QT_LOGGING_RULES="kwin_colorcorrection.debug=true"

Run from the terminal the following two commands
    qdbus org.kde.kded5 /kded unloadModule colorcorrectlocationupdater
    qdbus org.kde.kded5 /kded loadModule colorcorrectlocationupdater

Reviewers: #kwin, davidedmundson

Reviewed By: #kwin, davidedmundson

Subscribers: kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D24236

colorcorrection/manager.cpp

@@ -825,6 +825,8 @@ bool Manager::changeConfiguration(QHash<QString, QVariant> data)
 
 void Manager::autoLocationUpdate(double latitude, double longitude)
 {
+    qCDebug(KWIN_COLORCORRECTION, "Received new location (lat: %f, lng: %f)", latitude, longitude);
+
     if (!checkLocation(latitude, longitude)) {
         return;
     }