package/polkit: install polkit.loc to HOST_DIR

package/polkit: install polkit.loc to HOST_DIR

Fix added by commit c20d31baf471daeeec50d62cb8baa79bac06fa51 is
incomplete as polkit.loc must also be added to
$(HOST_DIR)/share/gettext/its

Additionally, the destination path for "$(INSTALL) -D" must be a
fully-qualified filename, not just the destination directory.

Fixes:
 - http://autobuild.buildroot.org/results/170e4802b7b4e8e7dafa95ade549e8fd05e43bfd

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
[yann.morin.1998@free.fr: dest must be a filename, not a directory]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>