Verify that all released package.xml files are parsable and valid

gistfile1.py

from catkin_pkg.package import parse_package_string
import rosdistro

i = rosdistro.get_index(rosdistro.get_index_url())
for distro in ['groovy', 'hydro', 'indigo']:
    print(distro)
    d = rosdistro.get_cached_distribution(i, distro)
    f = d._distribution_file
    for name in sorted(f.release_packages.keys()):
        xml = d.get_release_package_xml(name)
        if xml is None:
            continue
        try:
            pkg = parse_package_string(xml)
        except Exception as e:
            print(name, str(e))