Dark theme: make application output error message text color readable.

It was a pure red, which is really hard to read against a dark
background. This patch makes it a pastel red, closer to the fatal
error text color.

Change-Id: If4b402b2887149f040a00a9493f550afb296382b
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

share/qtcreator/themes/dark.creatortheme

@@ -86,7 +86,7 @@ OutputPanes_DebugTextColor=text
 OutputPanes_ErrorMessageTextColor=ffff6c6c
 OutputPanes_MessageOutput=ff008787
 OutputPanes_NormalMessageTextColor=text
-OutputPanes_StdErrTextColor=error
+OutputPanes_StdErrTextColor=ffff6666
 OutputPanes_StdOutTextColor=text
 OutputPanes_WarningMessageTextColor=fff3c300
 OutputPaneButtonFlashColor=error