Deploy to Docker from master even without a tag

[yurishkuro]

Which problem is this PR solving?

Resolves #1952. We used to publish snapshots on all commits to master, but now seem to only publish on tags, likely after https://github.com/jaegertracing/jaeger/pull/1909/files#diff-aeee4566b9eb012ce98bd3578f7740a3L26.

Short description of the changes

There is a call to ./scripts/travis/upload-all-docker-images.sh from before_deploy, but deploy is configured to only run on a tag, so before_deploy is probably also skipped on master. Moving this step back into script.

[codecov]

Codecov Report

Merging #1953 into master will decrease coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1953      +/-   ##
==========================================
- Coverage   98.46%   98.44%   -0.03%     
==========================================
  Files         199      199              
  Lines        9875     9875              
==========================================
- Hits         9723     9721       -2     
- Misses        116      117       +1     
- Partials       36       37       +1

Impacted Files	Coverage Δ
...lugin/sampling/strategystore/adaptive/processor.go	99.2% <0%> (-0.8%)	⬇️
plugin/storage/badger/spanstore/reader.go	96.79% <0%> (ø)	⬆️

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