Execute mp reboot prior to host dump delete service

The entries for the dumps stored in the host memory needs to
be deleted during a power off but that should be skipped
in the case of a memory preserving reboot.

Add changes to make sure the host dump clear service
executes after enter mp reboot service, so dump clear
service can be skipped if the indicater file exists.

Tests:
Feb 24 11:38:53 systemd[1]: Finished Start memory preserving reboot host0.
Feb 24 11:38:53 systemd[1]: Condition check resulted in Remove host dump entries during poweroff being skipped.

Signed-off-by: Dhruvaraj Subhashchandran <dhruvaraj@in.ibm.com>
Change-Id: I736a2c6245b494db054b086a1b63348838d926a7
diff --git a/service_files/op-enter-mpreboot@.service.in b/service_files/op-enter-mpreboot@.service.in
index 06a22b8..9582f52 100644
--- a/service_files/op-enter-mpreboot@.service.in
+++ b/service_files/op-enter-mpreboot@.service.in
@@ -7,6 +7,7 @@
 Before=op-stop-instructions@%i.service
 After=phosphor-reset-sensor-states@%i.service
 Before=phosphor-reboot-host@%i.service
+Before=clear_hostdumps_poweroff.service
 After=openpower-update-bios-attr-table.service
 Conflicts=obmc-host-startmin@%i.target