Fixed more lint found by clang static analyzer

char_class.c: Removed extraneous parens
account.h: Removed nonnull attribute from function with no pointers
act.wizard.c: Removed gcc-specific nested functions
hell_hunter_spec.c: Removed unused variable
spec_procs.c: Rewrote check to remove ambiguity.  NPC thieves will
probably steal more from others.