Fixing part of #2130
Fixing part of #2130

This change makes sure the publish page won't crash if no visible field
is found. It display the entry id (system:id) instead.

blaXXabla/projet_test_symphony,mazedigital/jcilearn,michael-e/symphony-2,jonmifsud/symphony-2,BloodBrother/symphony-2,avanteweb/symphony-2,DavidForster/symphony-2,brendo/symphony-2,NikoMostWanted/symphony-2,jurajkapsz/symphony-2,jurajkapsz/symphony-2,jonmifsud/symphony-2,jensscherbl/symphony,DeuxHuitHuit/symphony-2,mazedigital/jcilearn,alexnantel88/symphony-2,ljonka/symphony-2,DavidForster/symphony-2,symphonycms/symphony-2,johnpuddephatt/symphony-2,twiro/symphony-2,mazedigital/jcilearn,bauhouse/sym-todo-list,avanteweb/symphony-2,ljonka/symphony-2,alexnantel88/symphony-2,NikoMostWanted/symphony-2,jensscherbl/symphony,twiro/symphony-2,blaXXabla/projet_test_symphony,bauhouse/sym-todo-list,symphonycms/symphony-2,brendo/symphony-2,roshinebagha/Symphony-Test,BloodBrother/symphony-2,roshinebagha/Symphony-Test,johnpuddephatt/symphony-2,DeuxHuitHuit/symphony-2,michael-e/symphony-2