file corruptions at 2019-3-15 at 5 oclock

[bart1]

Files seem to be empty for atleast 3 radars (frlep, bewid and czska) see #56

[bart1]

This might be related this file has a plausible size but is corrupt: https://lw-enram.s3-eu-west-1.amazonaws.com/de/umd/2019/03/15/05/deumd_vp_20190315T051000Z_0x5.h5 atleast in the sense that biorad cant read it

[bart1]

This is an other corrupt file frche_vp_20190315T051000Z_0x7.h5