Check the format of more printf-type functions

We already have these checks in many printf-type functions that have
prototypes which are in header files.  Add these same checks to some
more prototypes in header functions and to static functions in .c
files.

cc: Miklos Vajna <vmiklos@frugalware.org>
Signed-off-by: Tarmigan Casebolt <tarmigan+git@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

daemon.c

@@ -77,6 +77,7 @@ static void logreport(int priority, const char *err, va_list params)
 	}
 }
 
+__attribute__((format (printf, 1, 2)))
 static void logerror(const char *err, ...)
 {
 	va_list params;
@@ -85,6 +86,7 @@ static void logerror(const char *err, ...)
 	va_end(params);
 }
 
+__attribute__((format (printf, 1, 2)))
 static void loginfo(const char *err, ...)
 {
 	va_list params;