patchREADME: fix path to "gitcvs-migration.txt" and be more consistent

Before this patch the README suggested to look at "Documentation/gittutorial.txt" for the tutorial and to use "man git-commandname" for documentation of each command.

This was not consistent because the tutorial can also be available with "man gittutorial" if git is installed, and the documentation for each command can be available at "Documentation/git-commandname.txt" if git is not installed.

So this patch tries to be more consistent and also fix the path to the cvs-migration documentation that changed from "Documentation/cvs-migration.txt" to "Documentation/gitcvs-migration.txt".

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
---
 README |   14 +++++++++++---
 1 files changed, 11 insertions(+), 3 deletions(-)

	This comes from this discussion:

	http://thread.gmane.org/gmane.comp.version-control.git/104753/focus=104906

On Tuesday 24 February 2009 21:16:37 Christian Couder wrote:

 seems Ok to me, with a caveat — the information is correct,
 but the presentation has a (very minor!) problem (IM(H?)O).
 I find a bit confusing that whilst you type (e.g.):

    git help tutorial

 you don't type:

    git help commandname

 but (e.g.):

    git help log

 that is, the ‘commandname’ is a placeholder (variable), whilst
 the ‘tutorial’ is a literal (constant).  there doesn't seem to
 be a clear distinction made....?    if a clear distinction is
 to be made, it should be done in a consistent manner throughout
 the README.  however, after a brief glance, there does not seem
 to be any distinction made in the README, so this is minor nit.

cheers!
	-blf-

Thanks.