remove default separate_build_dir = True in flexiblas.py

Author: branfosj

easybuild/easyblocks/f/flexiblas.py

@@ -63,7 +63,6 @@ def extra_options():
                          "'imkl', which does not need to be a (build)dependency." +
                          "If not defined, use the list of dependencies.", CUSTOM],
         })
-        extra_vars['separate_build_dir'][0] = True
         return extra_vars
 
     def __init__(self, *args, **kwargs):