Add fwu update agent deployment for linux-pc/posix

The fwu update agent can be deployed in different
execution environments to suite platform requirements.
This commit adds a deployment where the fwu update
agent runs within a command-line app for Posix
environments where the firmware image file is accessible
via standard file io. Can be built to run in a native PC
environment to enable a disk image file to be inspected.

Signed-off-by: Julian Hall <julian.hall@arm.com>
Change-Id: I3a652c7ab201c5b7059f8dd1bb6b590e6d8c4c37
diff --git a/components/service/fwu/app/metadata_reader.cpp b/components/service/fwu/app/metadata_reader.cpp
index 6423aa9..d1507f5 100644
--- a/components/service/fwu/app/metadata_reader.cpp
+++ b/components/service/fwu/app/metadata_reader.cpp
@@ -77,8 +77,11 @@
 				}
 			}
 
-			if (!is_handled)
-				IMSG("No metadata recognised");
+			if (!is_handled) {
+
+				/* This is normal on first-boot */
+				status = -1;
+			}
 
 		} else
 			IMSG("Failed to read metadata volume");