tools: remove phosphor-ipmi-blobs dependency

The host tool depended on the BMC header: firmware_handler.hpp because
it defined the flags.  This header depends on phosphor-ipmi-blobs,
therefore the host-tool depends on this.  Move the flags into a separate
common header file and snip this dependency.

Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: Id2ad33a1611c02605a1ed5c695429d0451eb98d4
diff --git a/bmc/test/firmware_state_notyetstarted_unittest.cpp b/bmc/test/firmware_state_notyetstarted_unittest.cpp
index 54ab7f8..8681064 100644
--- a/bmc/test/firmware_state_notyetstarted_unittest.cpp
+++ b/bmc/test/firmware_state_notyetstarted_unittest.cpp
@@ -76,7 +76,7 @@
      * transported supported.
      */
     blobs::BlobMeta expected;
-    expected.blobState = FirmwareBlobHandler::UpdateFlags::ipmi;
+    expected.blobState = FirmwareFlags::UpdateFlags::ipmi;
     expected.size = 0;
 
     auto blobs = handler->getBlobIds();