ECOFF slurp_relocs thinko

ECOFF slurp_relocs thinko

In git commit 806470a219 I swapped the order of internal vs. external
relocs memory allocation in ecoff_slurp_reloc_table, the idea being
that the external reloc size can be sanity checked against file size.
However, that fails badly with bfd_alloc memory where releasing any
block also releases all more recently allocated blocks.

	* ecoff.c (ecoff_slurp_reloc_table): Malloc external_relocs so
	they can be freed without also freeing internal_relocs.