fix one more -Wsometimes-uninitialized
fix one more -Wsometimes-uninitialized

The problem is here that lily_raise() doesn't have the __attribute__ ((noreturn))
We really need to probe for that and use it.
Adding the NULL just silences the warning.

src/lily_parser.c:709:14: warning: variable 'cls' is used uninitialized whenever
      'if' condition is false [-Wsometimes-uninitialized]
    else if (lex->token == tk_integer)
             ^~~~~~~~~~~~~~~~~~~~~~~~
src/lily_parser.c:715:9: note: uninitialized use occurs here
    if (cls->flags & CLS_IS_VARIANT)
        ^~~
src/lily_parser.c:709:10: note: remove the 'if' if its condition is always true
    else if (lex->token == tk_integer)
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/lily_parser.c:705:20: note: initialize the variable 'cls' to silence this
      warning
    lily_class *cls;
                   ^
                    = NULL

FascinatedBox/lily,jesserayadkins/lily,jesserayadkins/lily,FascinatedBox/lily,FascinatedBox/lily,jesserayadkins/lily,FascinatedBox/lily