exclude site-packages from .rst file scanning (#820)
exclude site-packages from .rst file scanning (#820)

make test fails when finding .rst files from site packages installed
in the virtual environment
jkbrzt/httpie,PKRoma/httpie,jakubroztocil/httpie,jkbrzt/httpie,PKRoma/httpie,jakubroztocil/httpie,jkbrzt/httpie,jakubroztocil/httpie