fix doc navigation links

Change-Id: I0d05947ce6a9caef73c91ba9645bc305000a1794
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@qt.io>

doc/src/overview/creator-getting-started.qdoc

@@ -31,7 +31,7 @@
 
 /*!
     \contentspage {Qt Creator Manual}
-    \previouspage {Qt Creator Manual}
+    \previouspage index.html
     \page creator-getting-started.html
     \nextpage creator-overview.html
 

doc/src/projects/creator-projects-settings-overview.qdoc

@@ -31,7 +31,7 @@
 
 /*!
     \contentspage {Qt Creator Manual}
-    \previouspage creator-version-control.html
+    \previouspage creator-vcs-subversion.html
     \page creator-configuring-projects.html
     \nextpage creator-targets.html