Fix echo statement inside fedora template

We no longer use mirrors.kernel.org.
Commit f71e8f4 switched it to archives.fedoraproject.org

Signed-off-by: Nehal J Wani <nehaljw.kkd1@gmail.com>

templates/lxc-fedora.in

@@ -579,7 +579,7 @@ but appears to be non-functional.  Skipping...  It should be removed.
     if [[ ! -f ../LiveOS/squashfs.img ]]
     then
         echo "
-Downloading stage 0 LiveOS squashfs file system from mirrors.kernel.org...
+Downloading stage 0 LiveOS squashfs file system from archives.fedoraproject.org...
 Have a beer or a cup of coffee.  This will take a bit (~300MB).
 "
         sleep 3 # let him read it...