lib: remove pager.c from libcommon

lib: remove pager.c from libcommon

The libcommon is a binary archive to keep compilation and maintenance
simple. The library is not linked as shared or so. The unused symbols
are removed from binaries (for example, by "make install-strip").

But it isn't evident for license analyzers (and some humans) that the
library uses GPL and non-GPL stuff simultaneously. Let's avoid doubts
and keep pager.c (with GPL license) out of the archive

Signed-off-by: Karel Zak <kzak@redhat.com>