build: fix libpcp_web builds for older versions of bison
build: fix libpcp_web builds for older versions of bison

Drop use of the api.series line, it's not supported by all
bison versions and I don't want to jump through the hoops
added into libpcp here unless we really need to (someday).

adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp