Fix Ruby warnings

Miscellaneous warnings regarding Ruby syntax (shown in Ruby 2.1+)

lib/memcached/client.rb

@@ -149,7 +149,7 @@ module Memcached
       servers = [servers] if servers.is_a?(String)
       servers.map do |server|
         server = server.to_s
-        if server =~ /^[\w\d\.-]+(:\d{1,5}){0,2}$/
+        if server =~ /^[\w\.-]+(:\d{1,5}){0,2}$/
           host, port, _weight = server.split(":")
           # TODO weight
           [:tcp, host, port.to_i]

test/unit/memcached_experimental_test.rb

@@ -89,7 +89,7 @@ class MemcachedExperimentalTest # TODO
       value = "Test that we cannot get 0 bytes with a get_len call."
       @experimental_cache.set key, value, 0, false
       assert_raises(Memcached::Failure) do
-        result = @experimental_cache.get_len 0, key
+        @experimental_cache.get_len 0, key
       end
     end
   end
@@ -119,7 +119,7 @@ class MemcachedExperimentalTest # TODO
     server_get_len_capable do
       @experimental_binary_protocol_cache.set key, @value
       assert_raises(Memcached::ActionNotSupported) do
-        result = @experimental_binary_protocol_cache.get_len 2, key
+        @experimental_binary_protocol_cache.get_len 2, key
       end
     end
   end
@@ -173,7 +173,7 @@ class MemcachedExperimentalTest # TODO
       @experimental_binary_protocol_cache.set key_1, value_1, 0, false
       @experimental_binary_protocol_cache.set key_2, value_2, 0, false
       assert_raises(Memcached::ActionNotSupported) do
-        result = @experimental_binary_protocol_cache.get_len 2, keys
+        @experimental_binary_protocol_cache.get_len 2, keys
       end
     end
   end
@@ -191,9 +191,9 @@ class MemcachedExperimentalTest # TODO
 
   def test_get_len_failure
     server_get_len_capable do
-      value = "Test that we cannot use get_len without setting the :experimental_features config."
+      # Test that we cannot use get_len without setting the :experimental_features config
       assert_raises(NoMethodError) do
-        result = @cache.get_len 10, key
+        @cache.get_len 10, key
       end
     end
   end

test/unit/memcached_test.rb

@@ -260,7 +260,7 @@ class MemcachedTest # TODO
       cache.get(key2)
     rescue => e
       assert_equal Memcached::ServerIsMarkedDead, e.class
-      assert_match /localhost:43041/, e.message
+      assert_match(/localhost:43041/, e.message)
     end
 
     # Hit first server on retry
@@ -335,7 +335,7 @@ class MemcachedTest # TODO
       cache.get(key2)
     rescue => e
       assert_equal Memcached::ServerIsMarkedDead, e.class
-      assert_match /localhost:43041/, e.message
+      assert_match(/localhost:43041/, e.message)
     end
 
     assert_nothing_raised do
@@ -349,7 +349,7 @@ class MemcachedTest # TODO
       cache.get(key2)
     rescue => e
       assert_equal Memcached::ServerIsMarkedDead, e.class
-      assert_match /localhost:43041/, e.message
+      assert_match(/localhost:43041/, e.message)
     end
 
     assert_nothing_raised do
@@ -380,7 +380,7 @@ class MemcachedTest # TODO
       cache.get(key2)
     rescue => e
       assert_equal Memcached::ServerIsMarkedDead, e.class
-      assert_match /localhost:43041/, e.message
+      assert_match(/localhost:43041/, e.message)
     end
 
     sleep(2)
@@ -390,7 +390,7 @@ class MemcachedTest # TODO
       cache.get(key2)
     rescue => e
       assert_equal Memcached::ServerIsMarkedDead, e.class
-      assert_match /localhost:43041/, e.message
+      assert_match(/localhost:43041/, e.message)
     end
   ensure
     socket.close
@@ -443,7 +443,7 @@ class MemcachedTest # TODO
       cache.get(key2)
     rescue => e
       assert_equal Memcached::ServerIsMarkedDead, e.class
-      assert_match /localhost:43041/, e.message
+      assert_match(/localhost:43041/, e.message)
     end
 
     # Hit first server on retry