Use bfd_alloc for compressed section contents

Use bfd_alloc for compressed section contents

Compressed section contents should be bfd_alloced to avoid memory leak.
This patch replaces bfd_malloc and free with bfd_alloc and bfd_release
on compressed buffer in bfd_compress_section_contents.  There is still
a very small memory leak when compressed section isn't smaller.

	* compress.c (bfd_compress_section_contents): Replace bfd_malloc
	and free with bfd_alloc and bfd_release on compressed buffer.
	Release buffer if compressed section isn't smaller.