[popup] Correctly handle the case when the fallback transition is "none" -- Fixes #5189
[popup] Correctly handle the case when the fallback transition is "none" -- Fixes #5189

arschmitz/jquery-mobile,hinaloe/jqm-demo-ja,startxfr/jquery-mobile,startxfr/jquery-mobile,arschmitz/uglymongrel-jquery-mobile,hinaloe/jqm-demo-ja,arschmitz/jquery-mobile,arschmitz/uglymongrel-jquery-mobile,arschmitz/jquery-mobile,arschmitz/uglymongrel-jquery-mobile,startxfr/jquery-mobile,hinaloe/jqm-demo-ja