Don't loose 'yyaccept' when fallback and initial states coincide.

Don't loose 'yyaccept' when fallback and initial states coincide.

Before code generation each DFA state is assigned a specific action.
Actions are mutually exclussive except for one: inital state may
coincide with fallback state. The bug was in overriding fallback
action with initial action (we lost 'yyaccept' which cause the wrong
match).

The bug was found with '--skeleton'.