dylink.r2py is not importing attributes starting with underscore in case the of dy_import_module

[us341]

Following error gets raised when one try to get attribute starting with underscore using dy_link_module:
Exception (with type 'exceptions.AttributeError'): ImportedModule instance has no attribute '_foo'

e.g. inside a library with name lib1.r2py----
def _foo():
log("its working")

lib3.r2py tries to get _foo ----
lib1 = dy_import_module("lib1.r2py")
if callfunc=='initialize':
lib1._foo()

but works fine with dy_import_module_symbols
e.g. in lib2.r2py----
dy_import_module_symbols("lib1.r2py")

if callfunc=='initialize':
_foo();

this works fine----
output:
its working

inside dylink.r2py it needs to handle these two types of import differently. It should not skip attributes starting with underscore if the import type is dy_import_module.