Fix error in tooltip caused by trailing whitespace on variable name

Fixes this error

```
[2013-09-19 20:41:37,440 - INFO - codeintel] _hit_from_citdl:: found 'HabBusinessPeer.retrieveByBSubcategory' => <Element 'scope' at 0x7f88ac35dcf8> on (<Element 'scope' at 0x7f889cec26e0>, ['HabBusinessPeer'])
[2013-09-19 20:41:37,440 - INFO - codeintel]     calltips: ["retrieveByBSubcategory($bsubcategory_id, $state = '', $page = 1, $max = 10, $bcategory_id = false)"]
[2013-09-19 20:41:37,440 - INFO - codeintel] done eval: success
[2013-09-19 20:41:37,443 - INFO - codeintel] Autocomplete called (PHP) [calltips]
Traceback (most recent call last):
  File "/home/hugo/.config/sublime-text-3/Packages/SublimeCodeIntel/SublimeCodeIntel.py", line 882, in _callback
    callback(*ret)
  File "/home/hugo/.config/sublime-text-3/Packages/SublimeCodeIntel/SublimeCodeIntel.py", line 404, in _trigger
    tooltip(view, calltips, original_pos)
  File "/home/hugo/.config/sublime-text-3/Packages/SublimeCodeIntel/SublimeCodeIntel.py", line 209, in tooltip
    if var[0] == '$':
IndexError: string index out of range
```