Make ATTN service stop a non-fatal event

Return true always for request to stop the ATTN service. This is
needed to pass CI in cases where the ATTN service is not installed.

Tested: With change in place when op-stop-instructions service is
started verify that journal does not indicate a failure in
op-stop-instructions service specifically in current iteration of
hardware CI.

Signed-off-by: Ben Tyner <ben.tyner@ibm.com>
Change-Id: Id1852082c768dd742afb85098a2120bda1acb41b
diff --git a/service_files/op-stop-instructions@.service.in b/service_files/op-stop-instructions@.service.in
index 22e3f51..06b9f67 100644
--- a/service_files/op-stop-instructions@.service.in
+++ b/service_files/op-stop-instructions@.service.in
@@ -12,7 +12,7 @@
 RemainAfterExit=yes
 Type=oneshot
 TimeoutStartSec=20
-ExecStart=/bin/systemctl stop attn_handler.service
+ExecStart=/bin/sh -c 'systemctl stop attn_handler.service || true'
 ExecStart=/usr/bin/openpower-proc-control threadStopAll
 
 [Install]