[okular] fix qt5
Error: An exception occurred within a child process:
NameError: undefined local variable or method `qt' for #<Formulary::FormulaNamespacebe7547d369dff8a547e245346101d89e::Okular:0x000000012b05d080>
Error: An exception occurred within a child process:
NameError: undefined local variable or method `qt' for #<Formulary::FormulaNamespacebe7547d369dff8a547e245346101d89e::Okular:0x000000012b05d080>