fix(git-bulk): fix a bad integer expression (#1198)

Fix a logic error inside the `allowedargcount()` function. This function
may be called with one or two arguments. However, no default values are
assigned to `$1` and `$2` that are used inside a numerical comparison.
Therefore, when using a bad number of arguments for the following lines:

```
listall|purge) allowedargcount 1;;
addcurrent|removeworkspace) allowedargcount 2;;
```

Then, we would get the error `[: : integer expression expected`. To fix
this, we assign the 0 default value to `$1` and `$2`, such that we
trigger the error message destined to the user without any integer error
when there is a bad number of argument and that the function is called
with only 1 argument instead of 2.

Author: Pierre Ayoub

bin/git-bulk

@@ -129,7 +129,7 @@ function wsnameToCurrent () {
 
 # helper to check number of arguments.
 function allowedargcount () {
-	if [ "$paramcount" -ne "$1"  ] && [ "$paramcount" -ne "$2" ]; then
+	if [ "$paramcount" -ne "${1:-0}"  ] && [ "$paramcount" -ne "${2:-0}" ]; then
 		echo 1>&2 "error: wrong number of arguments" && usage;
 		exit 1;
 	fi