update: Save files in run filesystem

Instead of in saving files in root which is messy and logically
part of the cow space, save the files in a directory under /run
which will be mounted during init, runtime, and shutdown.

Signed-off-by: Milton Miller <miltonm@us.ibm.com>
diff --git a/common/recipes-phosphor/obmc-phosphor-initfs/files/obmc-update.sh b/common/recipes-phosphor/obmc-phosphor-initfs/files/obmc-update.sh
index efdd913..b066471 100755
--- a/common/recipes-phosphor/obmc-phosphor-initfs/files/obmc-update.sh
+++ b/common/recipes-phosphor/obmc-phosphor-initfs/files/obmc-update.sh
@@ -57,7 +57,7 @@
 
 rwdir=rw
 upper=$rwdir/cow
-save=save/${upper##*/}
+save=/run/save/${upper##*/}
 
 doclean=
 dosave=y