Bug#753328: remove explicit baloo dependency from libraries

[Jonathan Riddell <jr@jriddell.org>]

Package: baloo

In the initial packaging I added an explicit dependency in the
.symbols files so anything using a baloo library would depend on
baloo.  Upstream has said this is wrong to do as it's perfectly valid
to not have baloo installed and be running e.g. dolphin.  Also
baloo-kf5 will be appearing sometime which is should be a drop in
replacement.  So it should rather be seeded in whatever meta-package is
installed for people to install a Plasma and KDE Software desktop.

Jonathan