bzip2/lzma: handle failures from bzip2 and lzma correctly

Impact: Bug fix

If bzip2 or lzma fails (for example, if they aren't installed on the
system), we need to propagate the failure out to "make".  However,
they were masked by being followed by a semicolon.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>