package/python-decorator: python3 is also needed for host

Commit 7bfe142e0d84400e386286347afd6e26f90b8aae forgot to set
HOST_PYTHON_DECORATOR_NEEDS_HOST_PYTHON

Fixes:
 - http://autobuild.buildroot.org/results/d11433a8076798d6088f92716608ebbe1c6aee9c

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

package/python-decorator/python-decorator.mk

@@ -12,6 +12,7 @@ PYTHON_DECORATOR_LICENSE_FILES = LICENSE.txt
 PYTHON_DECORATOR_CPE_ID_VENDOR = python
 PYTHON_DECORATOR_CPE_ID_PRODUCT = decorator
 PYTHON_DECORATOR_SETUP_TYPE = setuptools
+HOST_PYTHON_DECORATOR_NEEDS_HOST_PYTHON = python3
 
 $(eval $(python-package))
 $(eval $(host-python-package))