Documentation: update tar.umask default

As noted by Mike Hommey, the documentation for the config setting tar.umask
is not up-to-date.  Commit f08b3b0e changed
the default from 0 to 2; this patch finally documents it.
Signed-off-by: NRene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Documentation/config.txt

@@ -675,15 +675,11 @@ showbranch.default::
 	See gitlink:git-show-branch[1].
 
 tar.umask::
-	By default, gitlink:git-tar-tree[1] sets file and directories modes
-	to 0666 or 0777. While this is both useful and acceptable for projects
-	such as the Linux Kernel, it might be excessive for other projects.
-	With this variable, it becomes possible to tell
-	gitlink:git-tar-tree[1] to apply a specific umask to the modes above.
-	The special value "user" indicates that the user's current umask will
-	be used. This should be enough for most projects, as it will lead to
-	the same permissions as gitlink:git-checkout[1] would use. The default
-	value remains 0, which means world read-write.
+	This variable can be used to restrict the permission bits of
+	tar archive entries.  The default is 0002, which turns off the
+	world write bit.  The special value "user" indicates that the
+	archiving user's umask will be used instead.  See umask(2) and
+	gitlink:git-archive[1].
 
 user.email::
 	Your email address to be recorded in any newly created commits.

Documentation/git-archive.txt

@@ -72,16 +72,13 @@ zip
 
 CONFIGURATION
 -------------
-By default, file and directories modes are set to 0666 or 0777 in tar
-archives.  It is possible to change this by setting the "umask" variable
-in the repository configuration as follows :
 
-[tar]
-        umask = 002	;# group friendly
-
-The special umask value "user" indicates that the user's current umask
-will be used instead. The default value remains 0, which means world
-readable/writable files and directories.
+tar.umask::
+	This variable can be used to restrict the permission bits of
+	tar archive entries.  The default is 0002, which turns off the
+	world write bit.  The special value "user" indicates that the
+	archiving user's umask will be used instead.  See umask(2) for
+	details.
 
 EXAMPLES
 --------

Documentation/git-tar-tree.txt

@@ -42,16 +42,13 @@ OPTIONS
 
 CONFIGURATION
 -------------
-By default, file and directories modes are set to 0666 or 0777. It is
-possible to change this by setting the "umask" variable in the
-repository configuration as follows :
 
-[tar]
-        umask = 002	;# group friendly
-
-The special umask value "user" indicates that the user's current umask
-will be used instead.  The default value is 002, which means group
-readable/writable files and directories.
+tar.umask::
+	This variable can be used to restrict the permission bits of
+	tar archive entries.  The default is 0002, which turns off the
+	world write bit.  The special value "user" indicates that the
+	archiving user's umask will be used instead.  See umask(2) for
+	details.
 
 EXAMPLES
 --------