win32/rm.bat: remove each files

* win32/rm.bat: removing by wildcard errs on network file system, so
  remove each files.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38782 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

win32/rm.bat

@@ -6,7 +6,7 @@ if "%recursive%" == "1" goto :recursive
 :begin
 if "%1" == "" goto :end
 set p=%1
-if exist "%p:/=\%" del "%p:/=\%"
+if exist "%p:/=\%" for %%I in ("%p:/=\%") do @del "%%I"
 shift
 goto :begin
 :recursive