Javadoc
Parse a modify change type.
The grammar is : <changerecord> ::= "changetype:" FILL "modify" SEP
<mod-spec> <mod-specs-e> <mod-spec> ::= "add:" <mod-val> | "delete:"
<mod-val-del> | "replace:" <mod-val> <mod-specs-e> ::= <mod-spec>
<mod-specs-e> | e <mod-val> ::= FILL ATTRIBUTE-DESCRIPTION SEP
ATTRVAL-SPEC <attrval-specs-e> "-" SEP <mod-val-del> ::= FILL
ATTRIBUTE-DESCRIPTION SEP <attrval-specs-e> "-" SEP <attrval-specs-e> ::=
ATTRVAL-SPEC <attrval-specs> | e