Don't mis-match method calls as member accesses

Two rules matched both $a->foo and $a->foo(), but they were apparently
intended to only match the former.

Compare:

  $foo = $this->getRequest();
  $foo = $this->request;

"getRequest" should have a scope of "meta.function-call.php",
"request" should have "variable.other.property.php". Before this
patch, both get the latter. I don't understand how this works well
enough, but it seems that the two rules that I modified here matched
first and superseded the correct ones.
Merge pull request #9 from MatmaRex/patch-1

Don't mis-match method calls as member accesses