notes.h: declare bit field as unsigned to silence compiler complaints
notes.h: declare bit field as unsigned to silence compiler complaints

The IRIX MIPSPro compiler complains like this:

   cc-1107 c99: WARNING File = notes.h, Line = 215
     A signed bit field has a length of 1 bit.

           int suppress_default_notes:1;
               ^

'unsigned' is what was intended, so lets make it so.

Signed-off-by: Brandon Casey <77bc9a9984e6786c5799d7a71768cf023120ef76@nrlssc.navy.mil>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git