Remove URI backport for Ruby 1.9.3 (#1709)

Ruby 2.2+ has been a requirement since 825bf851f8

lib/puma/rack/backports/uri/common_193.rb

@@ -1,33 +0,0 @@
-# :stopdoc:
-
-require 'uri/common'
-
-# Issue:
-# http://bugs.ruby-lang.org/issues/5925
-#
-# Relevant commit:
-# https://github.com/ruby/ruby/commit/edb7cdf1eabaff78dfa5ffedfbc2e91b29fa9ca1
-
-
-module URI
-  begin
-    256.times do |i|
-      TBLENCWWWCOMP_[i.chr] = '%%%02X' % i
-    end
-    TBLENCWWWCOMP_[' '] = '+'
-    TBLENCWWWCOMP_.freeze
-
-    256.times do |i|
-      h, l = i>>4, i&15
-      TBLDECWWWCOMP_['%%%X%X' % [h, l]] = i.chr
-      TBLDECWWWCOMP_['%%%x%X' % [h, l]] = i.chr
-      TBLDECWWWCOMP_['%%%X%x' % [h, l]] = i.chr
-      TBLDECWWWCOMP_['%%%x%x' % [h, l]] = i.chr
-    end
-    TBLDECWWWCOMP_['+'] = ' '
-    TBLDECWWWCOMP_.freeze
-  rescue Exception
-  end
-end
-
-# :startdoc:

lib/puma/util.rb

@@ -1,11 +1,6 @@
 # frozen_string_literal: true
-major, minor, patch = RUBY_VERSION.split('.').map { |v| v.to_i }
 
-if major == 1 && minor == 9 && patch == 3 && RUBY_PATCHLEVEL < 125
-  require 'puma/rack/backports/uri/common_193'
-else
-  require 'uri/common'
-end
+require 'uri/common'
 
 module Puma
   module Util