BUG: Fix itk_module_config for repeated calls
BUG: Fix itk_module_config for repeated calls

Fix use of _${ns}_${mod}_USED settings to block reporting a module more
than once in a single itk_module_config call.  Do not leak the
_${ns}_${mod}_USED settings outside a single call to itk_module_config
so that a future call to the macro with the same ${ns} will use a fresh
set of modules.

Change-Id: I422e415f45db877512a0dcd3c588d9f74d32f515

fedral/ITK,Kitware/ITK,LucasGandel/ITK,BRAINSia/ITK,blowekamp/ITK,zachary-williamson/ITK,msmolens/ITK,ajjl/ITK,hjmjohnson/ITK,jcfr/ITK,ajjl/ITK,jmerkow/ITK,biotrump/ITK,BRAINSia/ITK,jmerkow/ITK,malaterre/ITK,atsnyder/ITK,biotrump/ITK,LucHermitte/ITK,jmerkow/ITK,BlueBrain/ITK,msmolens/ITK,thewtex/ITK,stnava/ITK,vfonov/ITK,BlueBrain/ITK,richardbeare/ITK,fbudin69500/ITK,malaterre/ITK,vfonov/ITK,blowekamp/ITK,zachary-williamson/ITK,fedral/ITK,atsnyder/ITK,atsnyder/ITK,richardbeare/ITK,fedral/ITK,hendradarwin/ITK,stnava/ITK,jcfr/ITK,InsightSoftwareConsortium/ITK,jmerkow/ITK,zachary-williamson/ITK,hendradarwin/ITK,malaterre/ITK,LucasGandel/ITK,hjmjohnson/ITK,vfonov/ITK,hjmjohnson/ITK,thewtex/ITK,LucHermitte/ITK,malaterre/ITK,spinicist/ITK,BlueBrain/ITK,fedral/ITK,vfonov/ITK,hjmjohnson/ITK,BRAINSia/ITK,Kitware/ITK,spinicist/ITK,ajjl/ITK,ajjl/ITK,zachary-williamson/ITK,heimdali/ITK,InsightSoftwareConsortium/ITK,BRAINSia/ITK,stnava/ITK,Kitware/ITK,blowekamp/ITK,vfonov/ITK,hendradarwin/ITK,LucasGandel/ITK,jmerkow/ITK,thewtex/ITK,spinicist/ITK,malaterre/ITK,spinicist/ITK,ajjl/ITK,LucasGandel/ITK,thewtex/ITK,ajjl/ITK,richardbeare/ITK,heimdali/ITK,fbudin69500/ITK,spinicist/ITK,LucasGandel/ITK,stnava/ITK,biotrump/ITK,fbudin69500/ITK,atsnyder/ITK,InsightSoftwareConsortium/ITK,malaterre/ITK,hjmjohnson/ITK,InsightSoftwareConsortium/ITK,jcfr/ITK,heimdali/ITK,msmolens/ITK,BlueBrain/ITK,atsnyder/ITK,PlutoniumHeart/ITK,biotrump/ITK,jcfr/ITK,atsnyder/ITK,fedral/ITK,ajjl/ITK,LucHermitte/ITK,stnava/ITK,msmolens/ITK,vfonov/ITK,msmolens/ITK,richardbeare/ITK,biotrump/ITK,PlutoniumHeart/ITK,zachary-williamson/ITK,spinicist/ITK,fbudin69500/ITK,hendradarwin/ITK,PlutoniumHeart/ITK,stnava/ITK,stnava/ITK,PlutoniumHeart/ITK,zachary-williamson/ITK,blowekamp/ITK,fbudin69500/ITK,hjmjohnson/ITK,jcfr/ITK,fbudin69500/ITK,BRAINSia/ITK,jcfr/ITK,LucHermitte/ITK,atsnyder/ITK,hendradarwin/ITK,jmerkow/ITK,BlueBrain/ITK,malaterre/ITK,jcfr/ITK,stnava/ITK,blowekamp/ITK,richardbeare/ITK,fedral/ITK,PlutoniumHeart/ITK,hendradarwin/ITK,fbudin69500/ITK,LucasGandel/ITK,msmolens/ITK,InsightSoftwareConsortium/ITK,LucHermitte/ITK,heimdali/ITK,malaterre/ITK,biotrump/ITK,LucHermitte/ITK,InsightSoftwareConsortium/ITK,PlutoniumHeart/ITK,LucasGandel/ITK,thewtex/ITK,hendradarwin/ITK,BlueBrain/ITK,jmerkow/ITK,hjmjohnson/ITK,heimdali/ITK,jcfr/ITK,blowekamp/ITK,hendradarwin/ITK,BlueBrain/ITK,thewtex/ITK,blowekamp/ITK,vfonov/ITK,PlutoniumHeart/ITK,thewtex/ITK,vfonov/ITK,Kitware/ITK,msmolens/ITK,spinicist/ITK,spinicist/ITK,PlutoniumHeart/ITK,heimdali/ITK,LucHermitte/ITK,Kitware/ITK,BlueBrain/ITK,atsnyder/ITK,ajjl/ITK,LucasGandel/ITK,heimdali/ITK,Kitware/ITK,richardbeare/ITK,Kitware/ITK,zachary-williamson/ITK,vfonov/ITK,malaterre/ITK,stnava/ITK,LucHermitte/ITK,jmerkow/ITK,biotrump/ITK,atsnyder/ITK,BRAINSia/ITK,BRAINSia/ITK,InsightSoftwareConsortium/ITK,zachary-williamson/ITK,blowekamp/ITK,msmolens/ITK,heimdali/ITK,spinicist/ITK,biotrump/ITK,fedral/ITK,fedral/ITK,zachary-williamson/ITK,fbudin69500/ITK,richardbeare/ITK