Fix the setXXXStream methods. If passed a null InputStream, convert

Fix the setXXXStream methods.  If passed a null InputStream, convert
this to a setNull call.  The code originally would try to read the
whole stream in one call to read(), but this doesn't work.  The
InputStream API makes it clear you must be prepared to loop and
continue reading if you didn't get the whole request on the first
try.

Per report from Martin Holz.