h5tojson.py can't convert TES-Aura_L2-O3-Nadir_r0000011015_F05_07.he5 file.

You can download the test file from here:

http://www.hdfgroup.uiuc.edu/ftp/pub/outgoing/NASAHDF/TES-Aura_L2-O3-Nadir_r0000011015_F05_07.he5

```
python h5tojson.py -d /mnt/ftp/pub/outgoing/NASAHDF/TES-Aura_L2-O3-Nadir_r0000011015_F05_07.he5 > /Users/hyoklee/src/hpd/TES-Aura_L2-O3-Nadir_r0000011015_F05_07.json
Traceback (most recent call last):
File "h5tojson.py", line 236, in
main()
File "h5tojson.py", line 233, in main
dumper.dumpFile()
File "h5tojson.py", line 188, in dumpFile
self.dumpDatasets()
File "h5tojson.py", line 154, in dumpDatasets
item = self.dumpDataset(uuid)
File "h5tojson.py", line 143, in dumpDataset
value = self.db.getDatasetValuesByUuid(uuid)
File "../server/hdf5db.py", line 1281, in getDatasetValuesByUuid
values = dset[slices].tolist() # just dump to list
File "h5py/_objects.pyx", line 54, in h5py._objects.with_phil.wrapper (/Users/travis/build/MacPython/h5py-wheels/h5py/h5py/_objects.c:2405)
File "h5py/_objects.pyx", line 55, in h5py._objects.with_phil.wrapper (/Users/travis/build/MacPython/h5py-wheels/h5py/h5py/_objects.c:2362)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/h5py/_hl/dataset.py", line 467, in __getitem__
self.id.read(mspace, fspace, arr, mtype)
File "h5py/_objects.pyx", line 54, in h5py._objects.with_phil.wrapper (/Users/travis/build/MacPython/h5py-wheels/h5py/h5py/_objects.c:2405)
File "h5py/_objects.pyx", line 55, in h5py._objects.with_phil.wrapper (/Users/travis/build/MacPython/h5py-wheels/h5py/h5py/_objects.c:2362)
File "h5py/h5d.pyx", line 175, in h5py.h5d.DatasetID.read (/Users/travis/build/MacPython/h5py-wheels/h5py/h5py/h5d.c:3004)
File "h5py/_proxy.pyx", line 150, in h5py._proxy.dset_rw (/Users/travis/build/MacPython/h5py-wheels/h5py/h5py/_proxy.c:1777)
File "h5py/_proxy.pyx", line 319, in h5py._proxy.needs_bkg_buffer (/Users/travis/build/MacPython/h5py-wheels/h5py/h5py/_proxy.c:3304)
File "h5py/_proxy.pyx", line 316, in h5py._proxy.needs_bkg_buffer (/Users/travis/build/MacPython/h5py-wheels/h5py/h5py/_proxy.c:3243)
KeyError: 'Conversion function not found (No appropriate function for conversion path)'
```