Remove use of legacy inventory interface

Made below given changes:
1.With legacy code we used to read software version info from the system
file: /etc/os-release, now with new updates we will read it from the
s/w object which is implementing the interface
"xyz.openbmc_project.Software.RedundancyPriority" interface.
2.Removed legacy code related to inventory(FRU) for sensors
Tested:
1.Verified f/w version info using below given command
  >ipmitool mc info -I dbus
2.Verified get sensor type info using below given command
  >ipmitool raw 0x04 0x2f 0x02 -I dbus

Resolves openbmc/openbmc#2870

Change-Id: I384bf4aaacd56f4a871833b533b2a8a68c489959
Signed-off-by: Nagaraju Goruganti <ngorugan@in.ibm.com>
2 files changed