Wrap EXPAND(..) macro with a do-while(0) loop and put a single statement on each line

As a positive side-effect, this eliminates the double semicolons reported by Coverity:
the macro contained a trailing semicolon, in addition to the semicolon placed on
each line where EXPAND(..) was called.

MFC after: 1 week
Reported by: Coverity
CID: 1194269
Sponsored by: EMC / Isilon Storage Division

usr.sbin/rpc.yppasswdd/yppasswdd_server.c

@@ -103,7 +103,10 @@ copy_yp_pass(char *p, int x, int m)
 	}
 
 	t = buf;
-#define EXPAND(e)       e = t; while ((*t++ = *p++));
+#define EXPAND(e) do { \
+	e = t; \
+	while ((*t++ = *p++)); \
+} while (0)
         EXPAND(yp_password.pw_name);
 	yp_password.pw_fields |= _PWF_NAME;
         EXPAND(yp_password.pw_passwd);