Fix a bug driving a LED during BMC boot

It is a requirement that Firmware notifies users about it's
READY state and the mechanism was to assert 'bmc_booted` group
which would result in user defined behavior on corresponding
physical LED. Blinking a particular physical LED is one of the
most common ways to let users know.

The code was asserting the 'bmc_booted' group soon after the LED
daemon was alive and this was incorrect since LED daemon would
start early in the boot and not after reaching READY state.

This patch waits until reaching READY before asserting the needed
LED group.

If applied, this commit will resolve openbmc/openbmc#1919 only for
systems that are not based on MRW. For fixing this issue on Witherspoon
machine, a change needs to be made in openbmc/phosphor-mrw-tools to
make sure latest XML is chosen during build. Currently, its pointing to
an old XML.

Change-Id: Idc711942140295f2cf5d7b691eb9371f4da671d5
Signed-off-by: Vishwanatha Subbanna <vishwa@linux.vnet.ibm.com>
diff --git a/meta-phosphor/common/recipes-phosphor/leds/phosphor-led-manager/bmc_booted.conf b/meta-phosphor/common/recipes-phosphor/leds/phosphor-led-manager/bmc_booted.conf
new file mode 100644
index 0000000..a300f6a
--- /dev/null
+++ b/meta-phosphor/common/recipes-phosphor/leds/phosphor-led-manager/bmc_booted.conf
@@ -0,0 +1,3 @@
+[Unit]
+Wants={SYSTEMD_DEFAULT_TARGET}
+After={SYSTEMD_DEFAULT_TARGET}