Echo output when pkg-map fails

When the call to pkg-map fails, it prints the error to stdout. However,
this output is lost when pkg-map is executed in a subshell, so the
actual error is never seen. This change adds an explicit echo so the
error is shown.

Change-Id: Id6f4fae6acadfe2839b408fb2dd11fb65d65df6e
Merge "Echo output when pkg-map fails"