only check our own input fields when determining to show the login button
only check our own input fields when determining to show the login button

fixes a problem with browser plugins adding hidden inputs

endsguy/server,andreas-p/nextcloud-server,owncloud/core,pixelipo/server,cernbox/core,lrytz/core,pmattern/server,cernbox/core,cernbox/core,pmattern/server,pixelipo/server,pmattern/server,bluelml/core,owncloud/core,Ardinis/server,owncloud/core,michaelletzgus/nextcloud-server,phil-davis/core,whitekiba/server,endsguy/server,IljaN/core,endsguy/server,bluelml/core,michaelletzgus/nextcloud-server,whitekiba/server,xx621998xx/server,xx621998xx/server,Ardinis/server,sharidas/core,pixelipo/server,lrytz/core,jbicha/server,IljaN/core,bluelml/core,pollopolea/core,cernbox/core,owncloud/core,sharidas/core,nextcloud/server,lrytz/core,Ardinis/server,jbicha/server,andreas-p/nextcloud-server,bluelml/core,whitekiba/server,sharidas/core,owncloud/core,jbicha/server,nextcloud/server,Ardinis/server,pixelipo/server,nextcloud/server,IljaN/core,endsguy/server,michaelletzgus/nextcloud-server,andreas-p/nextcloud-server,xx621998xx/server,jbicha/server,jbicha/server,IljaN/core,michaelletzgus/nextcloud-server,xx621998xx/server,whitekiba/server,pixelipo/server,lrytz/core,pollopolea/core,xx621998xx/server,andreas-p/nextcloud-server,Ardinis/server,bluelml/core,IljaN/core,andreas-p/nextcloud-server,endsguy/server,nextcloud/server,pmattern/server,pmattern/server,sharidas/core,pollopolea/core,sharidas/core,whitekiba/server,lrytz/core,cernbox/core,pollopolea/core,pollopolea/core