[ruby-cvs:72238] k0kubun:r65138 (trunk): .travis.yml: revert r65131 too

[k0kubun at ruby-lang.org]

k0kubun	2018-10-18 00:42:34 +0900 (Thu, 18 Oct 2018)

  New Revision: 65138

  https://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=revision&revision=65138

  Log:
    .travis.yml: revert r65131 too
    
    because it succeeded https://travis-ci.org/ruby/ruby/jobs/442733840.
    
    It looks that it randomly succeeds. Let's just leave it and see how
    stable it is, starting from `allow_failures` because it hasn't hanged
    only once so far.

  Modified files:
    trunk/.travis.yml