Refactoring: extract $PERF

Don't spell out the performance data multiple times.

check_lysrdiff

@@ -91,6 +91,8 @@ FAILED=`grep -c -- '--fail$' $state`
 STALE=`wc -l < $state-stale`
 ACTIVITY=`wc -l < $state-active`
 
+PERF="activity=$ACTIVITY stale=$STALE failed=$FAILED"
+
 if [ $FAILED -gt 10 ]
 then
   echo -n "CRITICAL - $FAILED failed backups"
@@ -105,7 +107,7 @@ then
 	  sz < 200 { printf "%s", $3; sz += length($3) }
 	  END { if (sz >= 200) printf ", others" } ' \
     |sed s'/, \([^,]*\)$/ and \1/'
-  echo '. | activity='$ACTIVITY stale=$STALE failed=$FAILED
+  echo ". | $PERF"
   rm $state $state-stale $state-active
   exit 2
 fi
@@ -123,7 +125,7 @@ then
 	  sz < 200 { printf "%s", $3; sz += length($3) }
 	  END { if (sz >= 200) printf ", others" } ' \
     |sed s'/, \([^,]*\)$/ and \1/'
-  echo '. | activity='$ACTIVITY stale=$STALE failed=$FAILED
+  echo ". | $PERF"
   rm $state $state-stale $state-active
   exit 2
 fi
@@ -142,7 +144,7 @@ then
 	  sz < 200 { printf "%s", $3; sz += length($3) }
 	  END { if (sz >= 200) printf ", others" } ' \
     |sed s'/, \([^,]*\)$/ and \1/'
-  echo '. | activity='$ACTIVITY stale=$STALE failed=$FAILED
+  echo ". | $PERF"
   rm $state $state-stale $state-active
 
   exit 1
@@ -157,18 +159,18 @@ then
 	  sz < 200 { printf "%s", $3; sz += length($3) }
 	  END { if (sz >= 200) printf ", others" } ' \
     |sed s'/, \([^,]*\)$/ and \1/'
-  echo '. | activity='$ACTIVITY stale=$STALE failed=0
+  echo ". | $PERF"
   rm $state $state-stale $state-active
   exit 1
 fi
 
 if [ $ACTIVITY = 0 ]
 then
-  echo 'WARNING - No activity. | activity='0 stale=$STALE failed=0
+  echo "WARNING - No activity. | $PERF"
   rm $state $state-stale $state-active
   exit 1
 fi
 
-echo 'OK - all ok. | activity='$ACTIVITY stale=0 failed=0
+echo "OK - all ok. | $PERF"
 rm $state $state-stale $state-active
 exit 0