ENH: ExternalData: Fix typo in unknown action error message
ENH: ExternalData: Fix typo in unknown action error message

s/Unnknown/Unknown/

Change-Id: I2cd43988962358f0add5653eeed83e21b384387f

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