Small cleanup in "/modules/mappers/mod_negotiation.c", in function get_body

[Christophe Jaillet]

In "/modules/mappers/mod_negotiation.c", in function get_body, arround line
857, we have :
    endbody += strlen(tag);

This could be replaced by :
    endbody += taglen;

because strlen(tag) has already been computed around line 835
    taglen = strlen(tag);

CJ