Use :bind instead of :socket_local to set local socket

lib/faraday/adapter/httpclient.rb

@@ -15,8 +15,8 @@ def call(env)
             configure_proxy proxy
           end
 
-          if sock = req[:socket_local]
-            configure_local_socket sock
+          if bind = req[:bind]
+            configure_socket bind
           end
 
           configure_timeouts req
@@ -41,9 +41,9 @@ def call(env)
         raise Faraday::Error::TimeoutError, $!
       end
 
-      def configure_local_socket(sock)
-        client.socket_local.host = sock[:host]
-        client.socket_local.port = sock[:port]
+      def configure_socket(bind)
+        client.socket_local.host = bind[:host]
+        client.socket_local.port = bind[:port]
       end
 
       def configure_proxy(proxy)

test/adapters/httpclient_test.rb

@@ -5,13 +5,12 @@ class HttpclientTest < Faraday::TestCase
 
     def adapter() :httpclient end
 
-    Integration.apply(self, :NonParallel)
-
-    def test_local_socket
-      adapter = Faraday::Adapter::HTTPClient.new
-      adapter.configure_local_socket({ :host => 'foo' })
-      assert_equal 'foo', adapter.client.socket_local.host
-      assert_nil adapter.client.socket_local.port
+    Integration.apply(self, :NonParallel) do
+      def test_binds_local_socket
+        host = '1.2.3.4'
+        conn = create_connection :request => { :bind => { :host => host } }
+        assert_equal host, conn.options[:bind][:host]
+      end
     end
   end
 end