Unescape private_key loaded from ENV (#132)

lib/googleauth/service_account.rb

@@ -58,7 +58,7 @@ module Google
         if json_key_io
           private_key, client_email = read_json_key(json_key_io)
         else
-          private_key = ENV[CredentialsLoader::PRIVATE_KEY_VAR]
+          private_key = unescape ENV[CredentialsLoader::PRIVATE_KEY_VAR]
           client_email = ENV[CredentialsLoader::CLIENT_EMAIL_VAR]
         end
 
@@ -78,6 +78,15 @@ module Google
         [json_key['private_key'], json_key['client_email']]
       end
 
+      # Handles certain escape sequences that sometimes appear in input.
+      # Specifically, interprets the "\n" sequence for newline, and removes
+      # enclosing quotes.
+      def self.unescape(str)
+        str = str.gsub '\n', "\n"
+        str = str[1..-2] if str.start_with?('"') && str.end_with?('"')
+        str
+      end
+
       def initialize(options = {})
         super(options)
       end