loongson/pypi: links for pipimport

loongson/mirror pipimport-0.2.5.tar.gz
loongson/mirror pipimport-0.2.4.tar.gz
loongson/mirror pipimport-0.2.3.tar.gz
loongson/mirror pipimport-0.2.2.tar.gz
loongson/mirror pipimport-0.2.1.tar.gz