Fix command not found in scripts lib

The successorator originally incremented RETRY with ((RETRY++)).
Bashate decided that was an ambiguous redirect  (why?, I don't care
about the output, I just want the variable to incremented). As a result
we changed the increment statement to $((RETRY++)), this increments the
variable, then tries to execute it, so the log contains:

"scripts/scripts-library.sh: line 51: 1: command not found"

I was going to add _=$((RETRY++)) but its getting ugly, so I replaced
the while loop with a c-style for loop that allows the increment
operator in the third statement.

Change-Id: I3db03dcefbcbe2b4c51e414f9fd2fee73e16a62e

scripts/scripts-library.sh

@@ -44,11 +44,9 @@ function successerator {
   set +e
   # Get the time that the method was started.
   OP_START_TIME=$(date +%s)
-  RETRY=0
   # Set the initial return value to failure.
   false
-  while [ $? -ne 0 -a ${RETRY} -lt ${MAX_RETRIES} ];do
-    $((RETRY++))
+  for ((RETRY=0; $? != 0 && RETRY < MAX_RETRIES; RETRY++)); do
     if [ ${RETRY} -gt 1 ];then
       $@ -vvvv
     else