wtperf parallel-pop-lsm failure

# wtperf options file: Run populate thread multi-threaded and with groups

# of operations in each transaction.

conn_config="cache_size=200MB"

table_config="lsm_chunk_size=1M,type=lsm"

transaction_config="isolation=snapshot"

icount=10000000

report_interval=5

stat_interval=4

run_time=20

populate_ops_per_txn=100

populate_threads=10

verbose=1

thread 15       execute_populate

thread 14       eviction server

thread 13       __wt_lsm_stat_init (waiting on LSM lock)

thread 12       failing thread

thread 11       failing thread

thread 1, 2, 3, 4, 5, 6, 7, 8, 9 10

                __clsm_put sleeping

                while (clsm->dsk_gen == lsm_tree->dsk_gen)

                        __wt_sleep(0, 10);

WT-4  0x0000000000478398 in __wt_abort (session=0x80204ba28)

    at ../src/os_posix/os_abort.c:21

WT-5  0x0000000000426597 in __wt_assert (session=Could not find the frame base for "__wt_assert".

) at ../src/support/err.c:408

WT-6  0x0000000000411f44 in __lsm_free_chunks (session=0x80204ba28, 

    lsm_tree=0x8023de600) at ../src/lsm/lsm_worker.c:621

WT-7  0x0000000000410b58 in __wt_lsm_merge_worker (vargs=0x80201e450)

    at ../src/lsm/lsm_worker.c:127

(gdb) frame 6

WT-6  0x0000000000411f44 in __lsm_free_chunks (session=0x80204ba28, 

    lsm_tree=0x8023de600) at ../src/lsm/lsm_worker.c:621

621			WT_ASSERT(session, lsm_tree->old_chunks[skipped] == chunk);

(gdb) p cookie

$13 = {chunk_array = 0x802619c00, chunk_alloc = 1280, nchunks = 82}

(gdb) p i

$14 = 75

(gdb) p skipped

$15 = 0

(gdb) p progress

$16 = 1

(gdb) p chunk

$99 = (WT_LSM_CHUNK *) 0x802728ce0

(gdb) p *chunk

$100 = 

{id = 269, generation = 1, uri = 0x8027e1540 "file:test-000269.lsm",

bloom_uri = 0x8027ed460 "file:test-000269.bf", count = 135834,

create_ts = { tv_sec = 1381325195, tv_nsec = 118098271},

refcnt = 1, txnid_max = 0, flags = 24}

(gdb) where

WT-5  0x0000000000426597 in __wt_assert (session=Could not find the frame base for "__wt_assert".

) at ../src/support/err.c:408

WT-6  0x0000000000411b1d in __lsm_discard_handle (session=0x80204b820, 

    uri=0x805ff32c0 "file:test-000243.lsm", checkpoint=0x0)

    at ../src/lsm/lsm_worker.c:491

WT-7  0x000000000041109f in __wt_lsm_checkpoint_worker (arg=0x8023de600)

    at ../src/lsm/lsm_worker.c:295

(gdb) frame 6

WT-6  0x0000000000411b1d in __lsm_discard_handle (session=0x80204b820, 

    uri=0x805ff32c0 "file:test-000243.lsm", checkpoint=0x0)

    at ../src/lsm/lsm_worker.c:491

491		WT_ASSERT(session, S2BT(session)->modified == 0);

(gdb) p ((WT_BTREE *)session->dhandle->handle)->modified

$191 = 1

(gdb) p session->dhandle->name

$192 = 0x805ff3340 "file:test-000243.lsm"

(gdb) frame 7

WT-7  0x000000000041109f in __wt_lsm_checkpoint_worker (arg=0x8023de600)

    at ../src/lsm/lsm_worker.c:295

295					if ((ret = __lsm_discard_handle(

(gdb) p *chunk

$193 = {id = 243, generation = 0, uri = 0x805ff32c0 "file:test-000243.lsm", 

  bloom_uri = 0x0, count = 10292, create_ts = {tv_sec = 1381325191, 

    tv_nsec = 118344315}, refcnt = 2, txnid_max = 19371, flags = 24}

(gdb) p chunk->flags & 0x10

$194 = 16

(gdb) p chunk->flags & 0x04

$195 = 0