package/gtest: fix host build

package/gtest: fix host build

Commit 9dfbbbb4105c47602da048c9bb9499fb8862e768 wrongly removed
dependency on host-python3 or host-python resulting in the following
build failure:

cp -rp /tmp/instance-2/output-1/build/host-gtest-1.11.0/googlemock/scripts/generator/cpp /tmp/instance-2/output-1/per-package/host-gtest/host/lib/python2.7/site-packages
cp: cannot create directory '/tmp/instance-2/output-1/per-package/host-gtest/host/lib/python2.7/site-packages': No such file or directory

Fixes:
 - http://autobuild.buildroot.org/results/a1d2e100a65d7c1c39c20bdd5bf687a804c94305

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>