meta-ibm: Use proper path names in service files

Don't use /usr/bin/env, it's an antipattern.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: If388f5427bb2ca45718d0ca99452bf3f147861dd
diff --git a/meta-ibm/recipes-phosphor/chassis/avsbus-control/mihawk/avsbus-disable@.service b/meta-ibm/recipes-phosphor/chassis/avsbus-control/mihawk/avsbus-disable@.service
index 5396948..c343fa1 100644
--- a/meta-ibm/recipes-phosphor/chassis/avsbus-control/mihawk/avsbus-disable@.service
+++ b/meta-ibm/recipes-phosphor/chassis/avsbus-control/mihawk/avsbus-disable@.service
@@ -7,8 +7,7 @@
 ConditionPathExists=!/run/openbmc/chassis@%i-on
 
 [Service]
-ExecStart=/usr/bin/env avsbus-disable.sh
-SyslogIdentifier=avsbus-disable.sh
+ExecStart=/usr/bin/avsbus-disable.sh
 Type=oneshot
 RemainAfterExit=yes