null equality matches on dotted queries different in 2.4 vs 2.5.5-pre

> db.repro.insert({ "_id" : 0, "c" : [ 0,1 ] })

> db.repro.find({"c.c":null})

{ "_id" : 0, "c" : [  0,  1 ] }

> db.version()

2.4.9

> db.repro.insert({ "_id" : 0, "c" : [ 0,1 ] })

> db.repro.find({"c.c":null})

> db.runCommand({"buildinfo": 1})

{

        "version" : "2.5.5-pre-",

        "gitVersion" : "f65a0b814b8c77e3fbe90bca0c061c9b77f6acdb",

        "OpenSSLVersion" : "",

        "sysInfo" : "Darwin Andrew-Emil-MacBook-Pro.local 12.4.0 Darwin Kernel Version 12.4.0: Wed May  1 17:57:12 PDT 2013; root:xnu-2050.24.15~1/RELEASE_X86_64 x86_64 BOOST_LIB_VERSION=1_49",

        "loaderFlags" : "-fPIC -pthread -Wl,-bind_at_load -mmacosx-version-min=10.6",

        "compilerFlags" : "-Wnon-virtual-dtor -Woverloaded-virtual -fPIC -fno-strict-aliasing -ggdb -pthread -Wall -Wsign-compare -Wno-unknown-pragmas -Winvalid-pch -Werror -pipe -O3 -Wno-unused-function -Wno-deprecated-declarations -mmacosx-version-min=10.6",

        "allocator" : "tcmalloc",

        "versionArray" : [

                2,

                5,

                5,

                -100

        ],

        "javascriptEngine" : "V8",

        "bits" : 64,

        "debug" : false,

        "maxBsonObjectSize" : 16777216,

        "ok" : 1

}