osx-keychain: fix compiler warning

Update git-credential-osxkeychain.c to remove 'format string is not a string
literal (potentially insecure)' compiler warning by treating the string as
an argument.

Signed-off-by: Lessley Dennington <[email protected]>
Acked-by: Derrick Stolee <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: ldennington

contrib/credential/osxkeychain/git-credential-osxkeychain.c

@@ -168,7 +168,7 @@ int main(int argc, const char **argv)
 		"usage: git credential-osxkeychain <get|store|erase>";
 
 	if (!argv[1])
-		die(usage);
+		die("%s", usage);
 
 	read_credential();