Add a changelog for the BC break

Change-Id: I768fcbbc871207e99466a2e1a9c7a67d98a2c897
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

dist/changes-5.0.1

@@ -1,5 +1,11 @@
 Qt 5.0.1 is a bug-fix release. It maintains both forward and backward
-compatibility (source and binary) with Qt 5.0.0.
+source compatibility with Qt 5.0.0.
+
+However, to fix a bug we detected after the 5.0 release, this release
+has a limited binary compatibility break. We therefore recommend all
+users to recompile their applications that provided QtMultimedia
+plugins or dealt with them directly. This is an exceptional case:
+compatibility will be kept for further releases.
 
 For more details, refer to the online documentation included in this
 distribution. The documentation is also available online:
@@ -22,8 +28,15 @@ information about a particular change.
 General Improvements
 --------------------
 
-Documentation: Various documentation fixes such as spelling and snippet
+ * Documentation: Various documentation fixes such as spelling and
-corrections.
+   snippet corrections.
+
+ * Fixed an issue that could cause memory leak when certain objects
+   were destroyed. The fix for this issue required a binary
+   compatibility break in two classes: QAudioSystemFactoryInterface
+   and QMediaServiceProviderFactoryInterface. Those two classes are
+   used only in QtMultimedia plugins and code directly dealing with
+   them and recompilation is only strictly necessary for them.
 
 Third party components
 ----------------------