Remove redundant method invocation.
Remove redundant method invocation.

Summary: `substring` uses end length of the string as a default anyways.

Reviewed By: styurin

fbshipit-source-id: 76ff9db4fd

rmaz/buck,JoelMarcey/buck,rmaz/buck,Addepar/buck,zpao/buck,rmaz/buck,brettwooldridge/buck,JoelMarcey/buck,romanoid/buck,SeleniumHQ/buck,JoelMarcey/buck,shs96c/buck,JoelMarcey/buck,romanoid/buck,romanoid/buck,Addepar/buck,Addepar/buck,kageiit/buck,brettwooldridge/buck,rmaz/buck,rmaz/buck,kageiit/buck,rmaz/buck,JoelMarcey/buck,romanoid/buck,romanoid/buck,brettwooldridge/buck,romanoid/buck,brettwooldridge/buck,rmaz/buck,rmaz/buck,rmaz/buck,JoelMarcey/buck,nguyentruongtho/buck,SeleniumHQ/buck,nguyentruongtho/buck,SeleniumHQ/buck,brettwooldridge/buck,shs96c/buck,JoelMarcey/buck,JoelMarcey/buck,romanoid/buck,SeleniumHQ/buck,nguyentruongtho/buck,kageiit/buck,shs96c/buck,Addepar/buck,rmaz/buck,SeleniumHQ/buck,JoelMarcey/buck,romanoid/buck,Addepar/buck,nguyentruongtho/buck,shs96c/buck,brettwooldridge/buck,facebook/buck,SeleniumHQ/buck,facebook/buck,romanoid/buck,nguyentruongtho/buck,brettwooldridge/buck,Addepar/buck,kageiit/buck,Addepar/buck,shs96c/buck,romanoid/buck,Addepar/buck,zpao/buck,rmaz/buck,JoelMarcey/buck,kageiit/buck,zpao/buck,zpao/buck,kageiit/buck,zpao/buck,shs96c/buck,brettwooldridge/buck,nguyentruongtho/buck,SeleniumHQ/buck,brettwooldridge/buck,rmaz/buck,brettwooldridge/buck,brettwooldridge/buck,zpao/buck,SeleniumHQ/buck,JoelMarcey/buck,Addepar/buck,SeleniumHQ/buck,shs96c/buck,zpao/buck,Addepar/buck,facebook/buck,romanoid/buck,Addepar/buck,shs96c/buck,brettwooldridge/buck,facebook/buck,brettwooldridge/buck,SeleniumHQ/buck,shs96c/buck,JoelMarcey/buck,Addepar/buck,rmaz/buck,JoelMarcey/buck,SeleniumHQ/buck,nguyentruongtho/buck,romanoid/buck,romanoid/buck,SeleniumHQ/buck,shs96c/buck,facebook/buck,facebook/buck,shs96c/buck,SeleniumHQ/buck,Addepar/buck,shs96c/buck,kageiit/buck,facebook/buck,shs96c/buck