pack partial_symtab for space

pack partial_symtab for space

This improves the packing of struct partial_symtab.  I noticed with
pahole that were were a couple of holes.  This consolidates the holes
without, I think, affecting readability -- it just moves the "user"
field a bit earlier in the struct.  This change saves a small amount
of memory.

2013-12-06  Tom Tromey  <tromey@redhat.com>

	* psympriv.h (struct partial_symtab) <user>: Move earlier.