Fix missing punctuation in docstring

This adds a period to the end of a docstring that was recently added and
swiftly merged to fix a bug in -rc2.

Change-Id: I399a72868911e03c6d69d9591ddcf7ee2d132fea
Merge "Fix missing punctuation in docstring"
Merge remote-tracking branch 'm_src_repo/master' into build-temp