use 'init' instead of 'init-db' for shipped docs and tools

While 'init-db' still is and probably will always remain a valid git
command for obvious backward compatibility reasons, it would be a good
idea to move shipped tools and docs to using 'init' instead.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/INSTALL b/INSTALL
index e7aea60..361c65b 100644
--- a/INSTALL
+++ b/INSTALL
@@ -95,7 +95,7 @@
    repository itself.  For example, you could:
 
 	$ mkdir manual && cd manual
-	$ git init-db
+	$ git init
 	$ git fetch-pack git://git.kernel.org/pub/scm/git/git.git man html |
 	  while read a b
 	  do