Doc cleanups.

Signed-off-by: Simon Hausmann <simon@lst.de>

contrib/fast-import/git-p4.txt

@@ -4,8 +4,8 @@ Usage
 =====
 
 git-p4 supports two main modes: Importing from Perforce to a Git repository is
-done using "git-p4 sync". Submitting changes from Git back to Perforce is
+done using "git-p4 sync" or "git-p4 rebase". Submitting changes from Git back
-done using "git-p4 submit".
+to Perforce is done using "git-p4 submit".
 
 Importing
 =========
@@ -49,10 +49,6 @@ a big import. This may take a while.
 Support for Perforce integrations is still work in progress. Don't bother
 trying it unless you want to hack on it :)
 
-For convenience there's also the git-p4 clone command that works similar to
-git-clone and combines the creation of the git repository with the the initial
-import and the branch setup
-
 Incremental Imports
 ===================