Yocto 2.3

Move OpenBMC to Yocto 2.3(pyro).

Tested: Built and verified Witherspoon and Palmetto images
Change-Id: I50744030e771f4850afc2a93a10d3507e76d36bc
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
Resolves: openbmc/openbmc#2461
diff --git a/import-layers/meta-openembedded/meta-oe/classes/machine_kernel_pr.bbclass b/import-layers/meta-openembedded/meta-oe/classes/machine_kernel_pr.bbclass
index 463b64d..e48bd01 100644
--- a/import-layers/meta-openembedded/meta-oe/classes/machine_kernel_pr.bbclass
+++ b/import-layers/meta-openembedded/meta-oe/classes/machine_kernel_pr.bbclass
@@ -1,6 +1,6 @@
 python __anonymous () {
 
-    machine_kernel_pr = d.getVar('MACHINE_KERNEL_PR', True)
+    machine_kernel_pr = d.getVar('MACHINE_KERNEL_PR')
 
     if machine_kernel_pr:
         d.setVar('PR', machine_kernel_pr)