HDFS-16564. Use uint32_t for hdfs_find (#4245)

* hdfs_find uses u_int32_t type for
  storing the value for the max-depth
  command line argument.
* The type u_int32_t isn't standard,
  isn't available on Windows and thus
  breaks cross-platform compatibility.
  We need to replace this with uint32_t
  which is available on all platforms since
  it's part of the C++ standard.

hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfspp/tools/hdfs-find/hdfs-find.cc

@@ -16,6 +16,7 @@
  * limitations under the License.
  */
 
+#include <cstdint>
 #include <future>
 #include <iostream>
 #include <memory>
@@ -40,7 +41,7 @@ bool Find::Initialize() {
       "If provided, all results will be matching the NAME pattern otherwise, "
       "the implicit '*' will be used NAME allows wild-cards");
   add_options(
-      "max-depth,m", po::value<u_int32_t>(),
+      "max-depth,m", po::value<uint32_t>(),
       "If provided, the maximum depth to recurse after the end of the path is "
       "reached will be limited by MAX_DEPTH otherwise, the maximum depth to "
       "recurse is unbound MAX_DEPTH can be set to 0 for pure globbing and "