[bazel][package] Better resource conflict err msgs

Print out all sources that are trying to install to the same
destination, instead of just one source.

Change-Id: I5e142fcdf6c8b34de1152908db6a3b556a6a6964
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1709771
Reviewed-by: David Dorwin <ddorwin@google.com>
Commit-Queue: Jay Zhuang <jayzhuang@google.com>
1 file changed