camtool list/sync: fix 3 bugs

1) revert to printing to stdout (broke in
08923e1c00a52a0d9caa7693b375b42789fed052) for actual output

2) do not warn about different identities when "syncing" to stdout

3) check blob was actually described before using its fields

Change-Id: Ibb3aa4c560e1b0036aba080807400e8820163cc9
Merge "camtool list/sync: fix 3 bugs"
C+A: add Antti Rasinen (Individual CLA)

Change-Id: I23c01f45741e8c856afe568476107e67debbc5ba