Fix two errors in Publish mode changing layout
Fix two errors in Publish mode changing layout

1) yellow screen if changing layout when no pdf displayed
2) in Upload mode, it was possible to check ALL of the layout modes

JohnThomson/BloomDesktop,StephenMcConnel/BloomDesktop,andrew-polk/BloomDesktop,BloomBooks/BloomDesktop,gmartin7/myBloomFork,JohnThomson/BloomDesktop,andrew-polk/BloomDesktop,StephenMcConnel/BloomDesktop,BloomBooks/BloomDesktop,StephenMcConnel/BloomDesktop,andrew-polk/BloomDesktop,gmartin7/myBloomFork,BloomBooks/BloomDesktop,JohnThomson/BloomDesktop,StephenMcConnel/BloomDesktop,StephenMcConnel/BloomDesktop,JohnThomson/BloomDesktop,andrew-polk/BloomDesktop,gmartin7/myBloomFork,JohnThomson/BloomDesktop,andrew-polk/BloomDesktop,StephenMcConnel/BloomDesktop,gmartin7/myBloomFork,BloomBooks/BloomDesktop,gmartin7/myBloomFork,gmartin7/myBloomFork,BloomBooks/BloomDesktop,BloomBooks/BloomDesktop,andrew-polk/BloomDesktop