www/proxygen: fix pkg-plist

pkg-static: Unable to access file /wrkdirs/usr/ports/www/proxygen/work/stage/usr/local/lib/liblibhttperf2.so.1.34.5:No such file or directory
pkg-static: Unable to access file /wrkdirs/usr/ports/www/proxygen/work/stage/usr/local/lib/libproxygen.so.1.34.5:No such file or directory
pkg-static: Unable to access file /wrkdirs/usr/ports/www/proxygen/work/stage/usr/local/lib/libproxygencurl.so.1.34.5:No such file or directory
pkg-static: Unable to access file /wrkdirs/usr/ports/www/proxygen/work/stage/usr/local/lib/libproxygendeviousbaton.so.1.34.5:No such file or directory
pkg-static: Unable to access file /wrkdirs/usr/ports/www/proxygen/work/stage/usr/local/lib/libproxygenhqloggerhelper.so.1.34.5:No such file or directory
pkg-static: Unable to access file /wrkdirs/usr/ports/www/proxygen/work/stage/usr/local/lib/libproxygenhqserver.so.1.34.5:No such file or directory
pkg-static: Unable to access file /wrkdirs/usr/ports/www/proxygen/work/stage/usr/local/lib/libproxygenhttpserver.so.1.34.5:No such file or directory