netd: Tweak .clang-format to match current style

The default value for ContinuationIndentWidth inherited from the Google
style is 4, but our IndentWidth is also 4, so it needs to be doubled.

Before:

 void forEachInterface(
     const std::string& dirname,
     const std::function<void(const std::string& path)) {
     fn(dirname, "default");
     DIR* dir = opendir(dirname.c_str());

With this patch:

 void forEachInterface(
         const std::string& dirname,
         const std::function<void(const std::string& path)) {
     fn(dirname, "default");
     DIR* dir = opendir(dirname.c_str());

Test: applied to server/*.cpp and compared output.
Change-Id: I8ce4e8415b4c76d1a895f82216783f50500b8129