Problem with modals without backdrop

[iolevsky]

Using 0.6.0 and 1.2.0.rc2

On line 1469 of ui-bootstrap-pls.js the variable backdropDomEl is undefined if backdrop is set to false at config time:

var modalInstance = $modal.open({ backdrop: false })

This is not being checked for in the IF statement on the line before. So when modalInstance.close() is called you get: TypeError: Cannot call method 'remove' of undefined

My solution is check for undefined:

    if (backdropIndex() == -1 && backdropDomEl !== undefined) {
      backdropDomEl.remove();
      backdropDomEl = undefined;
    }