Enable BMC patching from the /usr/local path

This commit enables patches from the /usr/local path by replacing
absolute paths to /usr/sbin or /usr/bin in every service file with
"/usr/bin/env ". Additionally, SyslogIdentifier is added to each
file to ensure that journal entries are still distinct.

In two cases, service files also had to change due to references
to ${{PATH}}, which doesn't work with /usr/bin/env. These
references - and the corresponding definitions - were changed to
${{DEVPATH}}.

Resolves openbmc/openbmc#2149

Change-Id: I12c5c6e5101eef6820b985a563313836250ff2c7
Signed-off-by: Michael Tritz <mtritz@us.ibm.com>
diff --git a/common/recipes-phosphor/chassis/obmc-mgr-inventory/obmc-sync-inventory-item@.service b/common/recipes-phosphor/chassis/obmc-mgr-inventory/obmc-sync-inventory-item@.service
index 33b1166..ba3af05 100644
--- a/common/recipes-phosphor/chassis/obmc-mgr-inventory/obmc-sync-inventory-item@.service
+++ b/common/recipes-phosphor/chassis/obmc-mgr-inventory/obmc-sync-inventory-item@.service
@@ -7,7 +7,8 @@
 Restart=no
 Type=oneshot
 EnvironmentFile={envfiledir}/obmc/sync_inventory_item/%I
-ExecStart={sbindir}/sync_inventory_items.py -t $FRU_TYPE -n $FRU_NAME -p ${{PROPERTY}} -s $SYNC_TYPE
+ExecStart=/usr/bin/env sync_inventory_items.py -t $FRU_TYPE -n $FRU_NAME -p ${{PROPERTY}} -s $SYNC_TYPE
+SyslogIdentifier=sync_inventory_items.py
 
 [Install]
 WantedBy={SYSTEMD_DEFAULT_TARGET}
diff --git a/common/recipes-phosphor/chassis/obmc-mgr-inventory/org.openbmc.Inventory.service b/common/recipes-phosphor/chassis/obmc-mgr-inventory/org.openbmc.Inventory.service
index 0f835a6..4a9232b 100644
--- a/common/recipes-phosphor/chassis/obmc-mgr-inventory/org.openbmc.Inventory.service
+++ b/common/recipes-phosphor/chassis/obmc-mgr-inventory/org.openbmc.Inventory.service
@@ -3,7 +3,8 @@
 
 [Service]
 Restart=always
-ExecStart={sbindir}/inventory_items.py
+ExecStart=/usr/bin/env inventory_items.py
+SyslogIdentifier=inventory_items.py
 Type=dbus
 BusName={BUSNAME}
 Environment="PYTHONUNBUFFERED=1"