Fixed typos

added the comma in line 54

Add context from:
https://github.com/thoughtbot/paperclip/issues/2021

[ci skip]

[ci skip]

Before the error message was sometimes millions of characters long.

> [paperclip] Content Type Spoof: Filename a.csv
> (application/octet-stream from Headers,
> [#<MIME::Type::Columnar:0x007f9f90f89fa8
> @container=#<MIME::Types:0x007f9f90b09d98 ... snip millions of
> characters of output here ...>], @content_type="text/csv",
> @raw_media_type="text", @raw_sub_type="csv", @simplified="text/csv",
> @i18n_key="text.csv", @media_type="text", @sub_type="csv",
> @extensions=["csv"]>] from Extension), content type discovered from
> file command: application/zip. See documentation to allow this
> combination.

Now becomes:

> [paperclip] Content Type Spoof: Filename a.csv
> (application/octet-stream from Headers,
> ["text/comma-separated-values", "text/csv"] from Extension), content
> type discovered from file command: application/zip. See documentation
> to allow this combination.

[fixes #2017]

update README.me: add missing 'end'

Paperclip works well with aws-sdk 1 and 2, and we default to 2.

[ci skip]

  $ rspec spec/paperclip/integration_spec.rb --profile 1
  Testing against version 4.1.7
  ..................................

  Finished in 15.19 seconds (files took 0.60155 seconds to load)
  34 examples, 0 failures

  Top 1 slowest examples (9.54 seconds, 62.8% of total time):
    Paperclip Many models at once does not exceed the open file limit
      9.54 seconds ./spec/paperclip/integration_spec.rb:18

to

  $ rspec spec/paperclip/integration_spec.rb --profile 1
  Testing against version 4.1.7
  ..................................

  Finished in 10.95 seconds (files took 0.59585 seconds to load)
  34 examples, 0 failures

  Top 1 slowest examples (5.33 seconds, 48.7% of total time):
    Paperclip Many models at once does not exceed the open file limit
      5.33 seconds ./spec/paperclip/integration_spec.rb:18

Updates gemfiles to Ruby 2 hash syntax.

[closes #1700]

Remove from Travis JRuby and Rubinius

They are allowed to fail, and they consistently fail. They only add up
time to our builds. If we wanted to keep them, they should be in the
build matrix and run tests successfully.

Removes note for running paperclip in EOL'd version of Rails (2.3).

Removes `column_type` and `column_options` so that it works well in both
versions.

Backcported from master, to release a patch version with this bugfix.

[closes #1947]

[fixes #1977]

README updated (for Debian-based Linux distros)

Other Debian based distros add in Ubuntu installation line

Test against Ruby 2.2.3 on Travis.

Removes `column_type` and `column_options` so that it works well in both
versions.

[closes #1947]

This reverts commit f6f5ea1b.

[closes #1966]

[closes #1965]

[fixes #1967]

Turns out it didn't fix test failures like I thought. It only added
more!

This reverts commit b8221c6b.