Fix Class-Cluster for Framebuffer Frame Generator
Fix Class-Cluster for Framebuffer Frame Generator

Summary:
The class-cluster was extracted, but never used. This results in the following exception:

```
2016-12-15 07:20:57.871 fbsimctl[6259:846506] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '-[FBFramebuffer_FrameGenerator_IOSurface jsonSerializableRepresentation] is abstract and should be overridden'
*** First throw call stack:
(
        0   CoreFoundation                      0x00007fff8406a6fb __exceptionPreprocess + 171
        1   libobjc.A.dylib                     0x00007fff98a0ea2a objc_exception_throw + 48
        2   CoreFoundation                      0x00007fff8406f252 +[NSException raise:format:arguments:] + 98
        3   Foundation                          0x00007fff85ac2390 -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:] + 195
        4   FBSimulatorControl                  0x000000010be1b1be -[FBFramebuffer jsonSerializableRepresentation] + 318
        5   FBSimulatorControl                  0x000000010be2f8cb -[FBSimulatorConnection jsonSerializableRepresentation] + 107
        6   FBSimulatorControlKit               0x000000010bbb7534 _TFV21FBSimulatorControlKit18ControlCoreSubjectg15jsonDescriptionOS_4JSON + 52
        7   FBSimulatorControlKit               0x000000010bbb7744 _TTWV21FBSimulatorControlKit18ControlCoreSubjectS_20EventReporterSubjectS_FS1_g15jsonDescriptionOS_4JSON + 52
        8   FBSimulatorControlKit               0x000000010bbb80df _TFV21FBSimulatorControlKit20iOSTargetWithSubjectg15jsonDescriptionOS_4JSON + 575
        9   FBSimulatorControlKit               0x000000010bbb86d7 _TTWV21FBSimulatorControlKit20iOSTargetWithSubjectS_20EventReporterSubjectS_FS1_g15jsonDescriptionOS_4JSON + 183
        10  FBSimulatorControlKit               0x000000010bbec480 _TFC21FBSimulatorControlKit17JSONEventReporter6reportfPS_20EventReporterSubject_T_ + 448
        11  FBSimulatorControlKit               0x000000010bbed5ca _TTWC21FBSimulatorControlKit17JSONEventReporterS_13EventReporterS_FS1_6reportfPS_20EventReporterSubject_T_ + 74
        12  FBSimulatorControlKit               0x000000010bbc0a58 _TFE21FBSimulatorControlKitPS_11iOSReporter6reportfTOS_9EventNameOS_9EventTypePS_20EventReporterSubject__T_ + 536
        13  FBSimulatorControlKit               0x000000010bbc0b91 _TFE21FBSimulatorControlKitPS_11iOSReporter11reportValuefTOS_9EventNameOS_9EventTypePSo18FBJSONSerializables23CustomStringConvertible__T_ + 209
        14  FBSimulatorControlKit               0x000000010bbefcb5 _TFC21FBSimulatorControlKit17SimulatorReporter20connectionDidConnectfCSo21FBSimulatorConnectionT_ + 101
        15  FBSimulatorControlKit               0x000000010bbefd0a _TToFC21FBSimulatorControlKit17SimulatorReporter20connectionDidConnectfCSo21FBSimulatorConnectionT_ + 58
        16  FBSimulatorControl                  0x000000010be50e09 -[FBMutableSimulatorEventSink connectionDidConnect:] + 89
        17  FBSimulatorControl                  0x000000010be2d1cb -[FBCompositeSimulatorEventSink connectionDidConnect:] + 363
        18  FBSimulatorControl                  0x000000010be4e19c -[FBSimulatorEventRelay connectionDidConnect:] + 748
        19  FBSimulatorControl                  0x000000010be71133 -[FBSimulatorBootStrategy boot:] + 1171
        20  FBSimulatorControl                  0x000000010be5afd1 __51-[FBSimulatorInteraction(Lifecycle) bootSimulator:]_block_invoke + 145
        21  FBSimulatorControl                  0x000000010be4c7db __61-[FBSimulatorInteraction interactWithSimulatorAtState:block:]_block_invoke + 427
        22  FBSimulatorControl                  0x000000010be4c4a9 __48-[FBSimulatorInteraction interactWithSimulator:]_block_invoke + 137
        23  FBControlCore                       0x000000010bf7ddcc __26-[FBInteraction interact:]_block_invoke + 76
        24  FBControlCore                       0x000000010bf7bfa0 -[FBInteraction_Block perform:] + 80
        25  FBControlCore                       0x000000010bf7c2e5 -[FBInteraction_Sequence perform:] + 373
        26  FBControlCore                       0x000000010bf7dfc6 -[FBInteraction perform:] + 70
        27  FBSimulatorControlKit               0x000000010bbd029d _TFFV21FBSimulatorControlKitP33_9EB6EA4AB2D754C6876358C126600E3E26SimulatorInteractionRunner3runFT_OS_13CommandResultU_FzT_T_ + 205
        28  FBSimulatorControlKit               0x000000010bc0b4d2 _TFC21FBSimulatorControlKit11Interaction7performfzT_T_ + 66
        29  FBSimulatorControlKit               0x000000010bc0b542 _TToFC21FBSimulatorControlKit11Interaction7performfzT_T_ + 50
        30  FBSimulatorControlKit               0x000000010bbe59f9 _TFV21FBSimulatorControlKit15iOSTargetRunner3runfT_OS_13CommandResult + 345
        31  FBSimulatorControlKit               0x000000010bbd015e _TFV21FBSimulatorControlKitP33_9EB6EA4AB2D754C6876358C126600E3E26SimulatorInteractionRunner3runfT_OS_13CommandResult + 462
        32  FBSimulatorControlKit               0x000000010bbd0483 _TTWV21FBSimulatorControlKitP33_9EB6EA4AB2D754C6876358C126600E3E26SimulatorInteractionRunnerS_6RunnerS_FS1_3runfT_OS_13CommandResult + 195
        33  FBSimulatorControlKit               0x000000010bbc391b _TFV21FBSimulatorControlKit21SimulatorActionRunner3runfT_OS_13CommandResult + 4891
        34  FBSimulatorControlKit               0x000000010bbcfbd8 _TTWV21FBSimulatorControlKit21SimulatorActionRunnerS_6RunnerS_FS1_3runfT_OS_13CommandResult + 1336
        35  FBSimulatorControlKit               0x000000010bc14a8f _TFV21FBSimulatorControlKit14SequenceRunner3runfT_OS_13CommandResult + 783
        36  FBSimulatorControlKit               0x000000010bc69636 _TFV21FBSimulatorControlKit12ActionRunner3runfT_OS_13CommandResult + 21846
        37  FBSimulatorControlKit               0x000000010bc61131 _TFV21FBSimulatorControlKit13CommandRunner3runfT_OS_13CommandResult + 6113
        38  FBSimulatorControlKit               0x000000010bc5f3e5 _TFV21FBSimulatorControlKit17BaseCommandRunner3runfT_OS_13CommandResult + 2549
        39  FBSimulatorControlKit               0x000000010bb9f339 _TFV21FBSimulatorControlKit9CLIRunner3runfT_OS_13CommandResult + 1257
        40  FBSimulatorControlKit               0x000000010bb9e44a _TFV21FBSimulatorControlKit9CLIRunner12runForStatusfT_Vs5Int32 + 42
        41  FBSimulatorControlKit               0x000000010bb9dee6 _TZFC21FBSimulatorControlKit15CLIBootstrapper9bootstrapfT_Vs5Int32 + 2390
        42  FBSimulatorControlKit               0x000000010bb9ed69 _TToZFC21FBSimulatorControlKit15CLIBootstrapper9bootstrapfT_Vs5Int32 + 25
        43  fbsimctl                            0x000000010bb89568 main + 56
        44  libdyld.dylib                       0x00007fff992eb255 start + 1
)
```

Reviewed By: asm89

Differential Revision: D4333648

fbshipit-source-id: 165eab219ac7aa131311fdc4f4f6579afa55d051

StevenUpForever/FBSimulatorControl,facebook/FBSimulatorControl,ichu501/FBSimulatorControl,plu/FBSimulatorControl,facebook/FBSimulatorControl,facebook/FBSimulatorControl,facebook/FBSimulatorControl,StevenUpForever/FBSimulatorControl,plu/FBSimulatorControl,plu/FBSimulatorControl,plu/FBSimulatorControl,StevenUpForever/FBSimulatorControl,facebook/FBSimulatorControl,StevenUpForever/FBSimulatorControl