If we need a FILE stream then get one...

If we need a FILE stream then get one...

- Replace the hysterical "lets see if the temp creation gave an fpio
  fd (it didn't), if not open another fd and then get its private
  FILE pointer" fiddling: since we need a FILE stream then open one
  with fdopen(), duh. Grabbing a rpmio fd to begin with is stupid enough
  when all we want is a stream, but wanting to use rpmMkTempFile()
  functionality...
- Also fixes an fd+mem leak in the unlikely but possible case that
  rpmMkTempFile() succeeds but fdopen() fails.