improve upload-pypi script

using TWINE_REPOSITORY makes it easier to have different sections in ones ~/.pypirc.

Author: ThomasWaldmann

util/upload-pypi

@@ -8,9 +8,9 @@ if [ "$R" = "" ]; then
 fi
 
 if [ "$2" = "test" ]; then
-    export TWINE_REPOSITORY_URL=https://test.pypi.org/legacy/
+    export TWINE_REPOSITORY=testpyfuse3
 else
-    export TWINE_REPOSITORY_URL=
+    export TWINE_REPOSITORY=pyfuse3
 fi
 
 D=dist/pyfuse3-$R.tar.gz