Fix for PR9751 to change the behavior of -Wformat warnings. If the format

string is part of the function call, then there is no difference.  If the
format string is not, the warning will point to the call site and a note
will point to where the format string is.

Fix-it hints for strings are moved to the note if a note is emitted.  This will
prevent changes to format strings that may be used in multiple places.

llvm-svn: 143168