Minor cleanup of logs/ plugins

* fix spelling mistake (thanks, codespell)
* do not hide exit code of command substitution via "local" (thanks, shellcheck)
* avoid access of potentially undefined variables (thanks, shellcheck)
* fix tabs/spaces
* avoid variable substitution in arithmetic substitution
* reduce number of successive blank lines at the top level down to two
* simplify evaluation of "printenv" output

plugins/logs/loggrepx_

@@ -83,14 +83,14 @@ OTHER DEALINGS IN THE SOFTWARE.
 =cut
 
 
-
 . "$MUNIN_LIBDIR/plugins/plugin.sh"
+
+regex=${regex:-}
+logfiles=${logfiles:-}
 LOGFILES="$(IFS= ; for f in $logfiles; do echo "$f"; done)"
 title="${title:-Log Matches}"
 
 
-
-
 function config() {
     echo "graph_title ${title}"
     echo "graph_args --base 1000 -l 0"
@@ -111,13 +111,12 @@ function config() {
 }
 
 
-
-
 function fetch() {
     # Load state
     touch "$MUNIN_STATEFILE"
-    local curstate="$(cat "$MUNIN_STATEFILE")"
     local nextstate=()
+    local curstate
+    curstate="$(cat "$MUNIN_STATEFILE")"
 
     local var_prefix logfile prvlines curlines matches
     while read -u 3 -r logfile; do
@@ -161,11 +160,7 @@ function fetch() {
 }
 
 
-
-
-
 case "$1" in
     config) config ;;
     *) fetch ;;
 esac
-