Remove nesting in Msf::DBManager::Migration

MSP-11124

To prevent migration.rb as counting as the definer of `Msf::DBManager`.

lib/msf/core/db_manager/migration.rb

@@ -1,59 +1,55 @@
 # -*- coding: binary -*-
-module Msf
-  class DBManager
-    module Migration
-      # Migrate database to latest schema version.
-      #
-      # @param verbose [Boolean] see ActiveRecord::Migration.verbose
-      # @return [Array<ActiveRecord::MigrationProxy] List of migrations that
-      #   ran.
-      #
-      # @see ActiveRecord::Migrator.migrate
-      def migrate(verbose=false)
-        ran = []
-        ActiveRecord::Migration.verbose = verbose
+module Msf::DBManager::Migration
+  # Migrate database to latest schema version.
+  #
+  # @param verbose [Boolean] see ActiveRecord::Migration.verbose
+  # @return [Array<ActiveRecord::MigrationProxy] List of migrations that
+  #   ran.
+  #
+  # @see ActiveRecord::Migrator.migrate
+  def migrate(verbose=false)
+    ran = []
+    ActiveRecord::Migration.verbose = verbose
 
-        ActiveRecord::Base.connection_pool.with_connection do
-          begin
-            ran = ActiveRecord::Migrator.migrate(
-                ActiveRecord::Migrator.migrations_paths
-            )
+    ActiveRecord::Base.connection_pool.with_connection do
+      begin
+        ran = ActiveRecord::Migrator.migrate(
+            ActiveRecord::Migrator.migrations_paths
+        )
           # ActiveRecord::Migrator#migrate rescues all errors and re-raises them
           # as StandardError
-          rescue StandardError => error
-            self.error = error
-            elog("DB.migrate threw an exception: #{error}")
-            dlog("Call stack:\n#{error.backtrace.join "\n"}")
-          end
-        end
-
-        # Since the connections that existed before the migrations ran could
-        # have outdated column information, reset column information for all
-        # ActiveRecord::Base descendents to prevent missing method errors for
-        # column methods for columns created in migrations after the column
-        # information was cached.
-        reset_column_information
-
-        return ran
-      end
-
-      # Flag to indicate database migration has completed
-      #
-      # @return [Boolean]
-      attr_accessor :migrated
-
-      private
-
-      # Resets the column information for all descendants of ActiveRecord::Base
-      # since some of the migrations may have cached column information that
-      # has been updated by later migrations.
-      #
-      # @return [void]
-      def reset_column_information
-        ActiveRecord::Base.descendants.each do |descendant|
-          descendant.reset_column_information
-        end
+      rescue StandardError => error
+        self.error = error
+        elog("DB.migrate threw an exception: #{error}")
+        dlog("Call stack:\n#{error.backtrace.join "\n"}")
       end
     end
+
+    # Since the connections that existed before the migrations ran could
+    # have outdated column information, reset column information for all
+    # ActiveRecord::Base descendents to prevent missing method errors for
+    # column methods for columns created in migrations after the column
+    # information was cached.
+    reset_column_information
+
+    return ran
   end
-end
+
+  # Flag to indicate database migration has completed
+  #
+  # @return [Boolean]
+  attr_accessor :migrated
+
+  private
+
+  # Resets the column information for all descendants of ActiveRecord::Base
+  # since some of the migrations may have cached column information that
+  # has been updated by later migrations.
+  #
+  # @return [void]
+  def reset_column_information
+    ActiveRecord::Base.descendants.each do |descendant|
+      descendant.reset_column_information
+    end
+  end
+end