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/dbus/phosphor-mapper/xyz.openbmc_project.ObjectMapper.service b/common/recipes-phosphor/dbus/phosphor-mapper/xyz.openbmc_project.ObjectMapper.service
index ccaaa98..820a42b 100644
--- a/common/recipes-phosphor/dbus/phosphor-mapper/xyz.openbmc_project.ObjectMapper.service
+++ b/common/recipes-phosphor/dbus/phosphor-mapper/xyz.openbmc_project.ObjectMapper.service
@@ -5,11 +5,12 @@
 [Service]
 Restart=always
 Type=dbus
-ExecStart={sbindir}/phosphor-mapper \
+ExecStart=/usr/bin/env phosphor-mapper \
         --path_namespaces="${{MAPPER_NAMESPACES}}" \
         --interface_namespaces="${{MAPPER_INTERFACES}}" \
         --blacklists="${{MAPPER_BLACKLISTS}}" \
         --interface_blacklists="${{MAPPER_INTERFACEBLACKLISTS}}"
+SyslogIdentifier=phosphor-mapper
 BusName={BUSNAME}
 TimeoutStartSec=300
 EnvironmentFile={envfiledir}/obmc/mapper