vl: Improve error message when we can't load fw_cfg from file

parse_fw_cfg() reports "can't load" without further details.  Get
the details from g_file_get_contents(), and include them in the
error message.

Signed-off-by: Li Qiang <liq3ea@gmail.com>
Message-Id: <1541051971-28584-1-git-send-email-liq3ea@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1 file changed