checkpkg: Clean up soname check output

A missing quote in a grep command was giving out false matches.

By moving the objdump command in the same echo statement as the
filename, we ensure that every library name are displayed on a line of
their own in case they don't have a SONAME defined in their
headers. That is the case for some plugin libraries.

Signed-off-by: Eric Bélanger <snowmaniscool@gmail.com>
Signed-off-by: Pierre Schmitz <pierre@archlinux.de>