rpmresolve.c: Fix unfreed pointers that keep DB opened

rpmresolve.c: Fix unfreed pointers that keep DB opened

There are some unfreed rpmmi pointers in printDepList()
function; this happens when the package have null as
the requirement.

This patch fixes these unfreed pointers and add small
changes to keep consistency with some variables.

[YOCTO #8028]

(From OE-Core rev: da7aa183f94adc1d0fff5bb81e827c584f9938ec)

Signed-off-by: Mariano Lopez <mariano.lopez@linux.intel.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>