mesa: update SRC_URI

mesa: update SRC_URI

ERROR: mesa-2_11.1.2-r0 do_checkuri: Function failed: Fetcher failure for URL: 'ftp://ftp.freedesktop.org/pub/mesa/11.1.2/mesa-11.1.2.tar.xz'. URL ftp://ftp.freedesktop.org/pub/mesa/11.1.2/mesa-11.1.2.tar.xz doesn't work
ERROR: Logfile of failure stored in: /home/akuster/oss/maint/poky/build/tmp/work/i586-poky-linux/mesa/2_11.1.2-r0/temp/log.do_checkuri.30779
Log data follows:
| DEBUG: Executing python function do_checkuri
| DEBUG: Testing URL ftp://ftp.freedesktop.org/pub/mesa/11.1.2/mesa-11.1.2.tar.xz
| DEBUG: checkstatus() urlopen failed: <urlopen error ftp error: 550 Failed to change directory.>
| DEBUG: Python function do_checkuri finished
| ERROR: Function failed: Fetcher failure for URL: 'ftp://ftp.freedesktop.org/pub/mesa/11.1.2/mesa-11.1.2.tar.xz'. URL ftp://ftp.freedesktop.org/pub/mesa/11.1.2/mesa-11.1.2.tar.xz doesn't work

Signed-off-by: Armin Kuster <akuster808@gmail.com>