fix bkenv has no effect bug when start bookie using bin/pulsar-daemon

[hangc0276]

when i start bookie using bin/pulsar-daemon start bookie command, i found the bookie environment variable defined in conf/bkenv.sh has no effect, but using $PULSAR_MEM and $PULSAR_GC instead.

Then i check the bin/pulsar shell script, i found as follow:

elif [ $COMMAND == "bookie" ]; then
    PULSAR_LOG_FILE=${PULSAR_LOG_FILE:-"bookkeeper.log"}
    # Pass BOOKIE_EXTRA_OPTS option defined in pulsar_env.sh
    OPTS="$OPTS $BOOKIE_EXTRA_OPTS"
    exec $JAVA $OPTS -Dpulsar.log.file=$PULSAR_LOG_FILE org.apache.bookkeeper.proto.BookieServer --conf $PULSAR_BOOKKEEPER_CONF $@

but in pulsar_env.sh, the $BOOKIE_EXTRA_OPTS defined as follow:

# Set BOOKIE_EXTRA_OPTS option here to ensure that all pulsar scripts can work seamless with bookkeeper

# Extra options to be passed to the jvm
BOOKIE_EXTRA_OPTS="${BOOKIE_EXTRA_OPTS} -Dio.netty.leakDetectionLevel=disabled -Dio.netty.recycler.maxCapacity.default=1000 -Dio.netty.recycler.linkCapacity=1024"

$BOOKIE_EXTRA_OPTS do not define $BOOKIE_MEM and $BOOKIE_GC, then the pulsar script will using $PULSAR_MEM and $PULSAR_GC instead to start bookkeeper.

So, i suggest to load conf/bkenv.sh in bin/pulsar script and using $BOOKIE_EXTRA_OPTS in conf/bkenv.sh instread of $BOOKIE_EXTRA_OPTS in bin/pulsar_env.sh

[sijie]

same comment as above

[merlimat]

This change is causing several side effects and I think it should be reverted.