Improve environment file formatting

[hrak]

This PR brings the contents of /etc/default/elasticsearch / /etc/sysconfig/elasticsearch more in line with the format that the Elasticsearch package uses. It removes quotes from vars that don't need it, and strips superfluous spaces from ES_JAVA_OPTS for a cleaner look. Tested on Ubuntu 14.04 and CentOS 6.

It also fixes a tiny cosmetic bug that resulted in env_options being included in ES_JAVA_OPTS because the default was '' instead of nil.

Before:

CONF_DIR="/etc/elasticsearch"
DATA_DIR="/usr/share/elasticsearch"
ES_GROUP="elasticsearch"
ES_HEAP_SIZE="496m"
ES_HOME="/usr/share/elasticsearch"
ES_JAVA_OPTS="-server -Djava.awt.headless=true -Djava.net.preferIPv4Stack=true -Xss256k      -XX:+UseParNewGC      -XX:+UseConcMarkSweepGC      -XX:CMSInitiatingOccupancyFraction=75      -XX:+UseCMSInitiatingOccupancyOnly      -XX:+HeapDumpOnOutOfMemoryError      -XX:+DisableExplicitGC  -Dfile.encoding=UTF-8 -Djna.nosys=true  "
ES_STARTUP_SLEEP_TIME="5"
ES_USER="elasticsearch"
LOG_DIR="/var/log/elasticsearch"
MAX_LOCKED_MEMORY="unlimited"
MAX_OPEN_FILES="64000"
PID_DIR="/var/run/elasticsearch"

After:

CONF_DIR=/etc/elasticsearch
DATA_DIR=/usr/share/elasticsearch
ES_GROUP=elasticsearch
ES_HEAP_SIZE=496m
ES_HOME=/usr/share/elasticsearch
ES_JAVA_OPTS="-server -Djava.awt.headless=true -Djava.net.preferIPv4Stack=true -Xss256k -XX:+UseParNewGC -XX:+UseConcMarkSweepGC -XX:CMSInitiatingOccupancyFraction=75 -XX:+UseCMSInitiatingOccupancyOnly -XX:+HeapDumpOnOutOfMemoryError -XX:+DisableExplicitGC -Dfile.encoding=UTF-8 -Djna.nosys=true"
ES_STARTUP_SLEEP_TIME=5
ES_USER=elasticsearch
LOG_DIR=/var/log/elasticsearch
MAX_LOCKED_MEMORY=unlimited
MAX_OPEN_FILES=64000
PID_DIR=/var/run/elasticsearch

[martinb3]

Thank you for the contribution!