cvsimport: sync usage lines with existing options

Sync both the usage lines in the code and the asciidoc
documentation with the real list of options. While
all options seems to be documented in the asciidoc
document, not all of them were listed in the usage line.

Signed-off-by: Frank Lichtenheld <frank@lichtenheld.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>

git-cvsimport.perl

@@ -36,8 +36,9 @@ sub usage() {
 	print STDERR <<END;
 Usage: ${\basename $0}     # fetch/update GIT from CVS
        [-o branch-for-HEAD] [-h] [-v] [-d CVSROOT] [-A author-conv-file]
-       [-p opts-for-cvsps] [-C GIT_repository] [-z fuzz] [-i] [-k] [-u]
-       [-s subst] [-a] [-m] [-M regex] [-S regex] [CVS_module]
+       [-p opts-for-cvsps] [-P file] [-C GIT_repository] [-z fuzz] [-i] [-k]
+       [-u] [-s subst] [-a] [-m] [-M regex] [-S regex] [-L commitlimit]
+       [CVS_module]
 END
 	exit(1);
 }