README: use 'https://' instead of 'git://'

When you clone the repository without previous commit history, 'git://'
doesn't protect from man-in-the-middle attacks.  HTTPS is more secure
since the client verifies the server certificate.

Reported-by: Jann Horn <jannh@google.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Message-id: 20181108111531.30671-2-stefanha@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
diff --git a/README b/README
index 49a9fd0..441c33e 100644
--- a/README
+++ b/README
@@ -54,7 +54,7 @@
 
 The QEMU source code is maintained under the GIT version control system.
 
-   git clone git://git.qemu.org/qemu.git
+   git clone https://git.qemu.org/git/qemu.git
 
 When submitting patches, one common approach is to use 'git
 format-patch' and/or 'git send-email' to format & send the mail to the
@@ -70,7 +70,7 @@
 
 The QEMU website is also maintained under source control.
 
-  git clone git://git.qemu.org/qemu-web.git
+  git clone https://git.qemu.org/git/qemu-web.git
   https://www.qemu.org/2017/02/04/the-new-qemu-website-is-up/
 
 A 'git-publish' utility was created to make above process less