loongson/pypi: links for libsnmp

loongson/mirror libsnmp-3.0.1.tar.gz
loongson/mirror libsnmp-3.0.1-py3-none-any.whl
loongson/mirror libsnmp-3.0.0.tar.gz
loongson/mirror libsnmp-3.0.0-py3-none-any.whl
loongson/mirror libsnmp-2.0.5.tar.gz
loongson/mirror libsnmp-2.0.5-py2.6.egg
loongson/mirror libsnmp-2.0.4.tar.gz