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/ipmi.cpp b/ipmi.cpp
index d297efc..509ec15 100644
--- a/ipmi.cpp
+++ b/ipmi.cpp
@@ -22,6 +22,7 @@
 #include "entity_name.hpp"
 #include "eth.hpp"
 #include "handler.hpp"
+#include "machine_name.hpp"
 #include "pcie_i2c.hpp"
 #include "psu.hpp"
 
@@ -63,6 +64,8 @@
             return pcieSlotI2cBusMapping(reqBuf, replyCmdBuf, dataLen, handler);
         case SysEntityName:
             return getEntityName(reqBuf, replyCmdBuf, dataLen, handler);
+        case SysMachineName:
+            return getMachineName(reqBuf, replyCmdBuf, dataLen, handler);
         default:
             std::fprintf(stderr, "Invalid subcommand: 0x%x\n", reqBuf[0]);
             return IPMI_CC_INVALID;