Fix a pair of Wfallthrough warnings in ScanfFormatString.

Change-Id: Ia73a34fdd93fc974224583505f9e6432493cb0da

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@350941 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed