fix Chksum.add() method also for perl/ruby
fix Chksum.add() method also for perl/ruby

jsilhan/libsolv,JacksonIsaac/libsolv,jsilhan/libsolv,JacksonIsaac/libsolv,JacksonIsaac/libsolv,jsilhan/libsolv,jsilhan/libsolv,jsilhan/libsolv,JacksonIsaac/libsolv,jsilhan/libsolv,JacksonIsaac/libsolv