Update default.conf

Replaced ARRAY=( "${ARRAY[@]}" additional elements )
with simpler and more fail safe ARRAY+=( additional elements )
see #2220

usr/share/rear/conf/default.conf

@@ -11,8 +11,8 @@
 #
 # Some variables are actually bash arrays and should be treated with care.
 # Use VAR=() to set an empty array.
-# Use VAR=( "${VAR[@]}" 'value' ) to add a fixed value to an array.
-# Use VAR=( "${VAR[@]}" "$var" ) to add a variable value to an array.
+# Use VAR+=( 'value' ) to add a fixed value to an array.
+# Use VAR+=( "$var" ) to add a variable value to an array.
 # Whether or not the latter case works as intended depends on when and
 # how "$var" is set and evaluated by the Relax-and-Recover scripts.
 # Be careful with values that are globbing patterns (cf. COPY_AS_IS below).
@@ -317,7 +317,7 @@ CHECK_CONFIG_FILES=( '/etc/drbd/' '/etc/drbd.conf' '/etc/lvm/lvm.conf' '/etc/mul
 # so that "curl -o recovery-update.tar.gz $RECOVERY_UPDATE_URL" will work.
 # Accordingly when using RECOVERY_UPDATE_URL="http://..."
 # curl should be added to the REQUIRED_PROGS array like
-#   REQUIRED_PROGS=( "${REQUIRED_PROGS[@]}" curl )
+#   REQUIRED_PROGS+=( curl )
 #
 # RECOVERY_UPDATE_URL is set to a default value here only
 # if not already set so that the user can set it also via
@@ -970,7 +970,7 @@ test "$BACKUP_PROG_ARCHIVE" || BACKUP_PROG_ARCHIVE="backup"
 # BACKUP_PROG_EXCLUDE is an array of strings that get written into a backup-exclude.txt file
 # that is used e.g. in 'tar -X backup-exclude.txt' to get things excluded from the backup.
 # Proper quoting of the BACKUP_PROG_EXCLUDE array members is crucial to avoid bash expansions.
-# In /etc/rear/local.conf use BACKUP_PROG_EXCLUDE=( "${BACKUP_PROG_EXCLUDE[@]}" '/this/*' '/that/*' )
+# In /etc/rear/local.conf use BACKUP_PROG_EXCLUDE+=( '/this/*' '/that/*' )
 # to specify your particular items that should be excluded from the backup in addition to what
 # gets excluded from the backup by default here (see also BACKUP_ONLY_EXCLUDE below):
 BACKUP_PROG_EXCLUDE=( '/tmp/*' '/dev/shm/*' "$VAR_DIR/output/*" )
@@ -1216,7 +1216,7 @@ UDEV_NET_MAC_RULE_FILES=( /etc/udev/rules.d/*persistent*{names,net,cd}.rules /et
 
 # Files and directories to copy as-is (with tar) into the ReaR recovery system.
 # Usually globbing patterns in COPY_AS_IS are specified without quoting
-# like COPY_AS_IS=( "${COPY_AS_IS[@]}" /my/directory/* /path/to/my/files* )
+# like COPY_AS_IS+=( /my/directory/* /path/to/my/files* )
 # so that the bash pathname expansion works as usually intended
 # (for details see the build/GNU/Linux/100_copy_as_is.sh script).
 # Because usr/sbin/rear sets the nullglob option globbing patterns
@@ -1986,8 +1986,8 @@ RSYNC_PROTOCOL_VERSION=
 #
 # The default rsync options passed (more can/will be added according workflow)
 # You can use this variable to add your own options, e.g.
-# BACKUP_RSYNC_OPTIONS=( "${BACKUP_RSYNC_OPTIONS[@]}" --devices --acls )
-BACKUP_RSYNC_OPTIONS=(--sparse --archive --hard-links --numeric-ids --stats)
+# BACKUP_RSYNC_OPTIONS+=( --devices --acls )
+BACKUP_RSYNC_OPTIONS=( --sparse --archive --hard-links --numeric-ids --stats )
 ############
 
 # Tape block size, default is to leave it up to the tape-device: