poky: Switch to post release name/version

This should have been done after Pyro was released, but it apparently
slipped though the cracks.

(From meta-yocto rev: 4e6dc6596fd60c35e14ad95899ebd66d16375d77)

Signed-off-by: Peter Kjellerstedt <peter.kjellerstedt@axis.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta-poky/conf/distro/poky.conf

@@ -1,7 +1,7 @@
 DISTRO = "poky"
 DISTRO_NAME = "Poky (Yocto Project Reference Distro)"
-DISTRO_VERSION = "2.3"
-DISTRO_CODENAME = "pyro"
+DISTRO_VERSION = "2.3+snapshot-${DATE}"
+DISTRO_CODENAME = "master"
 SDK_VENDOR = "-pokysdk"
 SDK_VERSION := "${@'${DISTRO_VERSION}'.replace('snapshot-${DATE}','snapshot')}"