Use RFC 2396 compatible URI parser for trustroot.

[tobiashm]

From Ruby 2.2 the default URI.parse method uses a new RFC 3986
compatible parser, which will parse most of the “invalid” URLs in the
trustroot test.

The URI::DEFAULT_PARSER references the “old” RFC 2396 compatible
URI parser in every version of Ruby I've tested.

Test script:

$ rvm 1.9.3,2.0.0,2.1,2.2,jruby,jruby-head,rbx do ruby -ruri -e "print %(#{RUBY_VERSION} : ); \
begin \
  URI::DEFAULT_PARSER.parse('http://*.schtuff.*/'); \
  p 'parsed'; \
rescue URI::InvalidURIError; \
  p 'invalid'; \
end"

Output:

1.9.3 : "invalid"
2.0.0 : "invalid"
2.1.5 : "invalid"
2.2.0 : "invalid"
1.9.3 : "invalid"
2.2.0 : "invalid"
2.1.0 : "invalid"

The same, using URI.parse instead, outputs:

1.9.3 : "invalid"
2.0.0 : "invalid"
2.1.5 : "invalid"
2.2.0 : "parsed"
1.9.3 : "invalid"
2.2.0 : "parsed"
2.1.0 : "invalid"

[jesperronn]

Travis failure caused by JRuby 1.7.18. Travis will now use JRuby 1.7.19, where the internal JRuby failure is fixed.

@dennisreimann could you please trigger Travis to restart the build?