shadowsocksr-libev: fix use-after-free due to a typo (#193)

shadowsocksr-libev/src/server/server.c

@@ -1943,7 +1943,7 @@ main(int argc, char **argv)
             memcpy(text, protocol, strlen(protocol) - 11);
             int length = strlen(protocol) - 11;
             free(protocol);
-            obfs = (char*)malloc(length);
+            protocol = (char*)malloc(length);
             memset(protocol, 0x00, length);
             memcpy(protocol, text, length);
             LOGI("protocol compatible enable, %s", protocol);