CLN: Remove tseries v0.19.0 deprecations

[gfyoung]

• Remove frequencies.get_standard_freq
• Drop the "freqstr" keyword from frequencies.to_offset

Deprecated in v0.19.0

xref #13874

[jreback]

rebase and push again, fixed some hanging by Travis CI

[gfyoung]

@jreback : Surprised master is doing okay. A lot of PR builds on Travis are getting hit with this "disk quota exceeded" error. Seems to be affecting a lot of other repositories though.

[jreback]

@gfyoung that was this morning. I think travis ci is having issues since then.

[gfyoung]

It's still happening though AFAICT. The PR build before mine has already failed on two builds with that exact same error.

https://travis-ci.org/pandas-dev/pandas/builds/323891129

[jreback]

see the Travis Status: https://twitter.com/traviscistatus?ref_src=twsrc%5Egoogle%7Ctwcamp%5Eserp%7Ctwgr%5Eauthor

still happening. FYI this is the Red icon on the travis page

[codecov]

Codecov Report

Merging #19023 into master will decrease coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #19023      +/-   ##
==========================================
- Coverage   91.57%   91.57%   -0.01%     
==========================================
  Files         150      150              
  Lines       48941    48935       -6     
==========================================
- Hits        44817    44811       -6     
  Misses       4124     4124

Flag	Coverage Δ
#multiple	89.93% <ø> (-0.01%)	⬇️
#single	41.75% <ø> (-0.01%)	⬇️

Impacted Files	Coverage Δ
pandas/tseries/frequencies.py	93.9% <ø> (-0.15%)	⬇️

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[gfyoung]

@jreback : Looks like Travis is up and running again. All is green now. PTAL.

[jreback]

thanks!