Packaging: Set elasticsearch homedir

This commit adds setting the homedir for the elasticsearch user to the
adduser command in the packaging preinstall script. While the
elasticsearch user is a system user, it is sometimes conventient to have
an existing homedir (even if it is not writeable). For example, running
cron as the elasticsearch user will try to change dir to the homedir.

closes elastic#14453

distribution/packages/src/common/scripts/preinst

@@ -27,6 +27,7 @@ case "$1" in
             adduser --quiet \
                     --system \
                     --no-create-home \
+                    --home-dir /usr/share/elasticsearch \
                     --ingroup elasticsearch \
                     --disabled-password \
                     --shell /bin/false \
@@ -50,8 +51,9 @@ case "$1" in
         # Create elasticsearch user if not existing
         if ! id elasticsearch > /dev/null 2>&1 ; then
             echo -n "Creating elasticsearch user..."
-            useradd -r \
-                    -M \
+            useradd --system \
+                    --no-create-home \
+                    --home-dir /usr/share/elasticsearch \
                     --gid elasticsearch \
                     --shell /sbin/nologin \
                     --comment "elasticsearch user" \

qa/vagrant/src/test/resources/packaging/utils/packages.bash

@@ -87,6 +87,8 @@ verify_package_installation() {
     id elasticsearch
 
     getent group elasticsearch
+    # homedir is set in /etc/passwd
+    assert_file $(getent passwd elasticsearch | cut -d: -f6) d root root 755
 
     assert_file "$ESHOME" d root root 755
     assert_file "$ESHOME/bin" d root root 755