Fix fpm to work with recent versions of pip

`--no-install` option has been removed from recent versions of pip.  Instead `pip download` should be used.

lib/fpm/package/python.rb

@@ -131,7 +131,7 @@ def download_if_necessary(package, version=nil)
                  "--build-directory", target, want_pkg)
     else
       logger.debug("using pip", :pip => attributes[:python_pip])
-      safesystem(attributes[:python_pip], "install", "--no-deps", "--no-install", "--no-use-wheel", "-i", attributes[:python_pypi], "-U", "--build", target, want_pkg)
+      safesystem(attributes[:python_pip], "download", "--no-clean", "--no-deps", "--no-binary", ":all:", "-i", attributes[:python_pypi], "--build", target,  want_pkg)
     end
 
     # easy_install will put stuff in @tmpdir/packagename/, so find that: