be compatible with peek-mysql2

don't use alias_method since peek-mysql2 uses prepend on rails >= 5
related to MiniProfiler#437 and MiniProfiler#444

lib/patches/db/mysql2.rb

@@ -1,30 +1,34 @@
 # frozen_string_literal: true
 
-# The best kind of instrumentation is in the actual db provider, however we don't want to double instrument
-
 class Mysql2::Result
-  alias_method :each_without_profiling, :each
-  def each(*args, &blk)
-    return each_without_profiling(*args, &blk) unless defined?(@miniprofiler_sql_id)
+  module MiniProfiler
+    def each(*args, &blk)
+      return super unless defined?(@miniprofiler_sql_id)
 
-    start        = Process.clock_gettime(Process::CLOCK_MONOTONIC)
-    result       = each_without_profiling(*args, &blk)
-    elapsed_time = SqlPatches.elapsed_time(start)
+      start        = Process.clock_gettime(Process::CLOCK_MONOTONIC)
+      result       = super
+      elapsed_time = SqlPatches.elapsed_time(start)
 
-    @miniprofiler_sql_id.report_reader_duration(elapsed_time)
-    result
+      @miniprofiler_sql_id.report_reader_duration(elapsed_time)
+      result
+    end
   end
+
+  prepend MiniProfiler
 end
 
 class Mysql2::Client
-  alias_method :query_without_profiling, :query
-  def query(*args, &blk)
-    return query_without_profiling(*args, &blk) unless SqlPatches.should_measure?
+  module MiniProfiler
+    def query(*args, &blk)
+      return super unless SqlPatches.should_measure?
 
-    result, record = SqlPatches.record_sql(args[0]) do
-      query_without_profiling(*args, &blk)
+      result, record = SqlPatches.record_sql(args[0]) do
+        super
+      end
+      result.instance_variable_set("@miniprofiler_sql_id", record) if result
+      result
     end
-    result.instance_variable_set("@miniprofiler_sql_id", record) if result
-    result
   end
+
+  prepend MiniProfiler
 end