Fix problem with on disk caching
Fix problem with on disk caching

Thanks @sklam for the suggestion!

stuartarchibald/numba,stuartarchibald/numba,gmarkall/numba,seibert/numba,sklam/numba,cpcloud/numba,numba/numba,cpcloud/numba,stuartarchibald/numba,sklam/numba,stuartarchibald/numba,jriehl/numba,jriehl/numba,gmarkall/numba,sklam/numba,sklam/numba,IntelLabs/numba,gmarkall/numba,stuartarchibald/numba,seibert/numba,IntelLabs/numba,stonebig/numba,cpcloud/numba,IntelLabs/numba,cpcloud/numba,numba/numba,jriehl/numba,numba/numba,gmarkall/numba,seibert/numba,jriehl/numba,numba/numba,stonebig/numba,jriehl/numba,seibert/numba,gmarkall/numba,stonebig/numba,sklam/numba,cpcloud/numba,stonebig/numba,IntelLabs/numba,stonebig/numba,seibert/numba,IntelLabs/numba,numba/numba