conc_update.js failure in slow weekly concurrency tests

assert.soon failed: function () {

    c2 = db.conc.count({x:{$lt:NRECORDS}});

    print(c2);

    querycount++;

    if (c2 < c1) {

        decrements++;

    } else {

        misses++;

    }

    c1 = c2;

    return !db.concflag.findOne().inprog;

}, msg:update never finished

Error("Printing Stack Trace")@:0

()@src/mongo/shell/utils.js:37

("assert.soon failed: function () {\n    c2 = db.conc.count({x:{$lt:NRECORDS}});\n    print(c2);\n    querycount++;\n    if (c2 < c1) {\n        decrements++;\n    } else {\n        misses++;\n    }\n    c1 = c2;\n    return !db.concflag.findOne().inprog;\n}, msg:update never finished")@src/mongo/shell/utils.js:58

((function () {c2 = db.conc.count({x:{$lt:NRECORDS}});print(c2);querycount++;if (c2 < c1) {decrements++;} else {misses++;}c1 = c2;return !db.concflag.findOne().inprog;}),"update never finished",3600000,10)@src/mongo/shell/utils.js:167

@/data/slave/Linux_64bit_concurrency_Weekly_Slow_Tests/mongo/jstests/slowWeekly/conc_update.js:50