DVR Crash

[sgpearse]

To reproduce:

1. Import the NetCDF-CF file /glade/campaign/cisl/vast/vapor/Bugs/3796/ss_for_vapor_205.nc
2. Create an enable a Volume Renderer

0   vapor                               0x00000001001d8c94 _Z16_segFaultHandleri + 56
1   libsystem_platform.dylib            0x000000019534d6a4 _sigtramp + 56
2   librender.dylib                     0x00000001011d0e54 _ZL15GetFaceVerticesRKN3glm3vecILi3EiLNS_9qualifierE0EEES4_PKfS4_RNS0_ILi3EfLS1_0EEES8_S8_S8_ + 200
3   librender.dylib                     0x00000001011d0e54 _ZL15GetFaceVerticesRKN3glm3vecILi3EiLNS_9qualifierE0EEES4_PKfS4_RNS0_ILi3EfLS1_0EEES8_S8_S8_ + 200
4   librender.dylib                     0x00000001011cf7e0 _ZL17ComputeSideBBoxesN3glm3vecILi3EiLNS_9qualifierE0EEEiiPNS0_ILi3EfLS1_0EEES4_PfRKS2_S7_ii + 536
5   librender.dylib                     0x00000001011cd26c _ZN5VAPoR19VolumeCellTraversal8LoadDataEPKNS_4GridE + 1772
6   librender.dylib                     0x000000010110d9ec _ZN5VAPoR14VolumeRenderer9_loadDataEv + 1796
7   librender.dylib                     0x000000010110cf30 _ZN5VAPoR14VolumeRenderer8_paintGLEb + 1740
8   librender.dylib                     0x000000010111b190 _ZN5VAPoR8Renderer7paintGLEb + 344
9   librender.dylib                     0x000000010114cd14 _ZN5VAPoR10Visualizer14renderRendererEPNS_8RendererEb + 112
10  librender.dylib                     0x000000010114d550 _ZN5VAPoR10Visualizer10paintEventEb + 1776
11  librender.dylib                     0x00000001010f458c _ZN5VAPoR11ControlExec5PaintENSt3__112basic_stringIcNS1_11char_traitsIcEENS1_9allocatorIcEEEEb + 216
12  vapor                               0x0000000100272a58 _ZN6VizWin13_renderHelperEb + 480