Fix velocity hourly IndexError

[mhidas]

This is an error that occurs when the time_deployment_start/end attributes in an input file represent a longer time span than what is actually covered by the data. Previously this could lead to the code trying to select and process an empty subset of the data.

[codecov]

Codecov Report

Merging #165 (7ee2483) into master (35e0167) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #165   +/-   ##
=======================================
  Coverage   84.86%   84.86%           
=======================================
  Files          12       12           
  Lines        1130     1130           
  Branches      156      156           
=======================================
  Hits          959      959           
  Misses        152      152           
  Partials       19       19           

Impacted Files	Coverage Δ
.../timeseries_products/velocity_hourly_timeseries.py	95.15% <100.00%> (ø)

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[mhidas]

@bpasquer @lbesnard My usual reviewer Leo is away, but this is just a very quick fix that should be pretty easy to review based on my explanation above. Any chance one of you could do a quick review?

[mhidas]

Thanks @bpasquer !