bios-updatesymlinks: Add Install section for WantedBy option

The WantedBy option was missing the Install section in the service
file, which was giving the following error:
flash-bios-updatesymlinks.service:9] Unknown lvalue 'WantedBy' in
section 'Service'

Also add a Before to specify the service to run before
the wanted by services.

Change-Id: Ic74c71b5bc166b85bfb45d51eb9bafca014f2e54
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
diff --git a/common/recipes-phosphor/flash/openpower-software-manager/obmc-flash-bios-updatesymlinks.service b/common/recipes-phosphor/flash/openpower-software-manager/obmc-flash-bios-updatesymlinks.service
index a7e2b7a..c0a2bbb 100644
--- a/common/recipes-phosphor/flash/openpower-software-manager/obmc-flash-bios-updatesymlinks.service
+++ b/common/recipes-phosphor/flash/openpower-software-manager/obmc-flash-bios-updatesymlinks.service
@@ -1,9 +1,12 @@
 [Unit]
 Description=Updates symlinks for active PNOR version
+Before=mboxd.service
+Before=mboxd-reload@.service
 
 [Service]
 Type=oneshot
 RemainAfterExit=no
 ExecStart={sbindir}/obmc-flash-bios updatesymlinks
 
+[Install]
 WantedBy=mboxd.service mboxd-reload@.service