Move the libraries into separate packages.

Creates the following additional packages: libzpool2, libnvpair1, libuutil1 and libzfs2.

Talk in Debian GNU/Linux concluded that there is no point in separating libzfs and libzfs_core. They are so dependent on each other that there is no/little point/requirement to have them separated. So <code>libzfs_core.so.1</code> is in the <code>libzfs2</code> package.

Visual inspection have shown everything is a-ok. Building and installing on Fedora20 works as well...

<code>
Fedora20ZFS-x64:/usr/src/zfs# rpm -iv `find *.{x86_64,noarch}.rpm | egrep -v 'devel|dracut|test|debug|dkms'`
Preparing packages...
libnvpair1-0.6.2-276_gbb2a918.fc20.x86_64
libuutil1-0.6.2-276_gbb2a918.fc20.x86_64
libzfs2-0.6.2-276_gbb2a918.fc20.x86_64
libzpool2-0.6.2-276_gbb2a918.fc20.x86_64
zfs-0.6.2-276_gbb2a918.fc20.x86_64
kmod-zfs-3.12.10-300.fc20.x86_64-0.6.2-276_gbb2a918.fc20.x86_64
</code>

Closes: #2329