Small fix in Texture3D's init method.
Small fix in Texture3D's init method.

RebeccaWPerry/vispy,dchilds7/Deysha-Star-Formation,julienr/vispy,inclement/vispy,jdreaver/vispy,srinathv/vispy,Eric89GXL/vispy,Eric89GXL/vispy,michaelaye/vispy,sbtlaarzc/vispy,sh4wn/vispy,Eric89GXL/vispy,jdreaver/vispy,jay3sh/vispy,dchilds7/Deysha-Star-Formation,kkuunnddaannkk/vispy,michaelaye/vispy,QuLogic/vispy,jdreaver/vispy,drufat/vispy,michaelaye/vispy,QuLogic/vispy,sbtlaarzc/vispy,drufat/vispy,kkuunnddaannkk/vispy,srinathv/vispy,bollu/vispy,QuLogic/vispy,inclement/vispy,RebeccaWPerry/vispy,drufat/vispy,julienr/vispy,sh4wn/vispy,RebeccaWPerry/vispy,bollu/vispy,kkuunnddaannkk/vispy,jay3sh/vispy,ghisvail/vispy,hronoses/vispy,hronoses/vispy,ghisvail/vispy,ghisvail/vispy,hronoses/vispy,inclement/vispy,srinathv/vispy,sh4wn/vispy,jay3sh/vispy,sbtlaarzc/vispy,bollu/vispy,julienr/vispy,dchilds7/Deysha-Star-Formation