Bug 882140 - [calendar] progress spinner: Text is too long 

there is a lint error caused because of the `display:inline` + `width` property.

check the `Li` result on [treeherder](https://treeherder.mozilla.org/ui/#/jobs?repo=gaia-try&revision=48e183fb9dea)
```
05:45:18     INFO -  apps/calendar/style/modify_account_view.css has new errors/warnings.
05:45:18     INFO -  Errors in /builds/slave/test/gaia/apps/calendar/style/modify_account_view.css
05:45:18     INFO -  	width can't be used with display: inline. line 35, col 3
05:45:26     INFO - TEST-UNEXPECTED-FAIL | make lint | make[1]: *** [csslint] Error 1
```