Update WXBaseViewController.m

[niceskylei]

fix bug #2922

[weex-bot]

	Warnings
⚠️	No Changelog changes! - Can you add a Changelog? To do so,append your changes to the changelog.md
⚠️	Current pr not bind the milestone
⚠️	If your PR is about fixing a bug excluding crash the code,you should add the demo link in the PR description. Demo link: http://dotwe.org/vue

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[YorkShen]

The CI failed, please check and fix it. @niceskylei