Add suppport for retrieving machine name

This adds support for reading /etc/os-release, parsing out
OPENBMC_TARGET_MACHINE and returning this to the caller.

Change-Id: If2a419b9a77597686f5137efce97b1150142f181
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/commands.hpp b/commands.hpp
index dfe8f29..e8f1efa 100644
--- a/commands.hpp
+++ b/commands.hpp
@@ -21,6 +21,8 @@
     SysPcieSlotI2cBusMapping = 5,
     // The Sys "entity id:entity instance" to entity name mapping command.
     SysEntityName = 6,
+    // Returns the machine name of the image
+    SysMachineName = 7,
 };
 
 } // namespace ipmi