Replaced the 'unicode' gem with 'unf' so it'll work with JRuby.

Fixes #2279: Remove dependency on "unicode" gem.

fog.gemspec

@@ -50,7 +50,7 @@ Gem::Specification.new do |s|
   s.add_dependency('net-ssh', '>=2.1.3')
   s.add_dependency('nokogiri', '~>1.5')
   s.add_dependency('ruby-hmac')
-  s.add_dependency('unicode', "~> 0.4.4") unless RUBY_PLATFORM == 'java'
+  s.add_dependency('unf')
 
   ## List your development dependencies here. Development dependencies are
   ## those that are only needed during development

lib/fog/aws.rb

@@ -1,11 +1,7 @@
 require 'fog/core'
 require 'fog/aws/credential_fetcher'
 require 'fog/aws/signaturev4'
-begin
-  require 'unicode'
-rescue LoadError
-  # Temporarily ignored.  This should only impact JRuby.
-end
+require 'unf/normalizer'
 
 module Fog
   module AWS
@@ -91,13 +87,7 @@ module Fog
     end
 
     def self.escape(string)
-      string = begin
-                 ::Unicode::normalize_C(string)
-               rescue
-                 Fog::Logger.warning("Fog::AWS string escaping will not normalize Unicode characters on JRuby, pending a fix for issue #2279")
-                 string
-               end
-
+      string = ::UNF::Normalizer.normalize(string, :nfc)
       string.gsub(/([^a-zA-Z0-9_.\-~]+)/) {
         "%" + $1.unpack("H2" * $1.bytesize).join("%").upcase
       }

lib/fog/aws/storage.rb

@@ -170,13 +170,7 @@ module Fog
 
         # NOTE: differs from Fog::AWS.escape by NOT escaping `/`
         def escape(string)
-          string = begin
-            ::Unicode::normalize_C(string)
-          rescue
-            Fog::Logger.warning("Fog::Storage::AWS string escaping will not normalize Unicode characters on JRuby, pending a fix for issue #2279")
-            string
-          end
-
+          string = ::UNF::Normalizer.normalize(string, :nfc)
           string.gsub(/([^a-zA-Z0-9_.\-~\/]+)/) {
             "%" + $1.unpack("H2" * $1.bytesize).join("%").upcase
           }