Revert "Add ability to check /etc/lsb-release for HWID"

This reverts commit d1da5101a191aa90fd671c9b9ab36573849a08e2.

Investigating a parrot in this state (from the bug) I discovered that if I specified HWID_OVERRIDE=tacos, hardware_class=tacos got sent in the omaha request. This must be an issue with either us passing define incorrectly or parsing it incorrectly. Reverting for now to be safe. 

BUG=chromium:344727
TEST=tested manually that the reason the bug is happening is because update_engine is respecting HWID_OVERRIDE

Change-Id: I18665abc93a8d88b1d73f56c1784971ff0d29b87
Reviewed-on: https://chromium-review.googlesource.com/187029
Reviewed-by: Chris Sosa <sosa@chromium.org>
Tested-by: Chris Sosa <sosa@chromium.org>
diff --git a/hardware.h b/hardware.h
index 8168d9c..2693e3b 100644
--- a/hardware.h
+++ b/hardware.h
@@ -14,8 +14,7 @@
 // Implements the real interface with the hardware.
 class Hardware : public HardwareInterface {
  public:
-  Hardware();
-  virtual ~Hardware();
+  Hardware() {}
 
   // HardwareInterface methods.
   virtual const std::string BootKernelDevice();