Emergency goobsdiff patch: don't use LZMA_RUN after LZMA_FINISH

Emergency goobsdiff patch: don't use LZMA_RUN after LZMA_FINISH.

In testing, cases were discovered where fread would read until EOF, but
lzma_code would not be able to decompress that entire block in one call
because not enough space was available in the output buffer. Calling lzma_code
with LZMA_FINISH followed by LZMA_RUN is incorrect. Once LZMA_FINISH is used
once, subsequent calls to lzma_code must also use LZMA_FINISH.

From <lzma/base.h>:

 * After the first use of LZMA_SYNC_FLUSH, LZMA_FULL_FLUSH, or LZMA_FINISH,
 * the same `action' must is used until lzma_code() returns LZMA_STREAM_END.
 * Also, the amount of input (that is, strm->avail_in) must not be modified
 * by the application until lzma_code() returns LZMA_STREAM_END. Changing the
 * `action' or modifying the amount of input will make lzma_code() return
 * LZMA_PROG_ERROR.

This bug caused goobspatch to exit prematurely with a message like

goobspatch: xzread(extra, 216): 11

11 is LZMA_PROG_ERROR.

BUG=47199
TEST=none

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=50537

[Mark Mentovai, 2010-06-22 22:31:40]

TBR (emergency)

[TVL, 2010-06-23 11:52:57]

lgtm