stop ATTN service during watchdog time out handling

A watchdog time out will initiate a dump. As a side-effect, the dump
will likely trigger a checkstop attention. We do not want ATTN to handle
this attention. So we are stopping the ATTN service before initiating
the dump. The ATTN service will be restarted on the next IPL.

Signed-off-by: Zane Shelley <zshelle@us.ibm.com>
Change-Id: If98ce1b3dfbf31896808b1a43ecc007efb6ea8f8
diff --git a/attn/attn_handler.service.in b/attn/attn_handler.service.in
index 44f4f6a..b100a34 100644
--- a/attn/attn_handler.service.in
+++ b/attn/attn_handler.service.in
@@ -7,6 +7,7 @@
 After=op-cfam-reset.service
 After=cfam_override@0.service
 Conflicts=obmc-host-stop@0.target
+Conflicts=obmc-host-timeout@0.target
 
 [Service]
 @ENABLE_PHAL_TRUE@Environment="PDBG_DTB=/var/lib/phosphor-software-manager/pnor/rw/DEVTREE"