Geneinfo service fails when chr = NaN (see gene KIR2DL2)

[tonydisera]

https://backend.iobio.io/geneinfo/KIR2DL2?source=refseq&build=GRCh38&species=homo_sapiens
gets 502 Bad Gateway

This is caused by errant data in the geneinfo.db. The transcripts chr column has a value of NaN for this gene. This is probably caused by incorrect loading logic for alternative contigs in the geneinfo db load. So we will need to fix that code and reload geneinfo db.

In the meantime, make the code in geneinfo service more robust so that this doesn't result in a failure, but that a gene with no transcripts (or some sort of warning).