Fix the anti-pattern in systemd service file

https://github.com/openbmc/docs/blob/master/anti-patterns.md#
use-of-usrbinenv-in-systemd-service-files

Signed-off-by: Tom Joseph <tomjoseph@in.ibm.com>
Change-Id: I121bdebce7c88db450b28d6a1afd4e3e7cc30816
1 file changed