The pkg_version explorer will fail to properly detect if a package
is installed when a package's name is present in the description of
a package (as returned by pkg_info).
Currently, trying to install libtool fails due to incorrect parsing:
$ pkg_info | grep libtool
libltdl-2.4.2p1 GNU libtool system independent dlopen wrapper
Additionally, trying to install nagios results in the following output:
$ pkg_info | grep nagios
nagios-4.0.8p3-chroot host and service monitor
nagios-web-4.0.8p2-chroot cgis and webpages for nagios
This commit fixes detection by properly parsing pkg_info's output.
Specifically, descriptions are ignored and package names are properly
extracted.