Fix a note without a SourceLocation.

#define TEST int y; int x = y;
void foo() {
  TEST
}

-Wuninitialized gives this warning:
invalid-loc.cc:4:3: warning: variable 'y' is uninitialized when used here
      [-Wuninitialized]
  TEST
  ^~~~
invalid-loc.cc:2:29: note: expanded from macro 'TEST'
#define TEST int y; int x = y;
                            ^
note: initialize the variable 'y' to silence this warning
1 warning generated.

The second note lacks filename, line number, and code snippet.  This change
will remove the fixit and only point to variable declaration.

invalid-loc.cc:4:3: warning: variable 'y' is uninitialized when used here
      [-Wuninitialized]
  TEST
  ^~~~
invalid-loc.cc:2:29: note: expanded from macro 'TEST'
#define TEST int y; int x = y;
                            ^
invalid-loc.cc:4:3: note: variable 'y' is declared here
  TEST
  ^
invalid-loc.cc:2:14: note: expanded from macro 'TEST'
#define TEST int y; int x = y;
             ^
1 warning generated.

llvm-svn: 156045