[patch, fortran, committed] Fix wrong warning inside associate construct

[Thomas Koenig]

Hello world,

I have committed the attached patch as obvious after regression-testing.

It removes the wrong warning from my recend DO warning patch that Jakub
pointed out.  The test case that is restored with this patch is enough
to catch any regression.

Regards

	Thomas

2017-09-26  Thomas Koenig  <tkoenig@gcc.gnu.org>

	* frontend-passes.c (do_subscript): Don't do anything
	if inside an associate list.

2017-09-26  Thomas Koenig  <tkoenig@gcc.gnu.org>

	* gfortran.dg/gomp/associate1.f90: Remove unnecessary
	warning from associate construct and do loop.