Fix mem leak when unserializing an arg in a function call fails.

Shouldn't be a typical scenario since hopefully we'd know about
and fix the underlying problem w/ unserialization...
Fix mem leak when failing to end a serialization.

We'd probably know about it if that actually ever happened in practice
(which it shouldn't).
Fix mem leak when unserializing table entry fails.

Shouldn't happen in practice.
Fix mem leak when merging incompatible types.

Though this would typically be caused by a scripting error that should
be fixed and Bro would exit anyway if encountered at parse time.
Fix mem leak in failing table initialization case.

Specifically that case looked like tables that have a compound index
and an element assignment fails due to a type mismatch.