Stop using deprecated "new_http_archive"

This function no longer exists at bazel HEAD. This patch replaces the
calls with the intended replacement from @bazel_tools.

Change-Id: I9429ac3de0c42b92b5b922d779e4fd6fb229ab71
diff --git a/WORKSPACE b/WORKSPACE
index 5857ece..dfe5a02 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -601,7 +601,7 @@
     urls = ["https://github.com/emscripten-core/emscripten/archive/" + emscripten_version + ".tar.gz"],
 )
 
-new_http_archive(
+http_archive(
     name = "emscripten_clang",
     build_file_content = """
 filegroup(
@@ -615,21 +615,21 @@
     url = "https://www.frc971.org/Build-Dependencies/emscripten-llvm-e" + emscripten_version + ".tar.gz",
 )
 
-new_http_archive(
+http_archive(
     name = "webrtc_x64",
     build_file = "@//debian:webrtc.BUILD",
     sha256 = "bd212b2a112a043d08d27f49027091788fa01c7c2ac5f072d096c17d9dbd976f",
     url = "https://www.frc971.org/Build-Dependencies/webrtc-30326-1a68679-linux-x64.tar.gz",
 )
 
-new_http_archive(
+http_archive(
     name = "webrtc_arm",
     build_file = "@//debian:webrtc.BUILD",
     sha256 = "c34badaf313877cd03a0dfd6b71de024d806a7652550a7f1cd7dea523a7c813d",
     url = "https://www.frc971.org/Build-Dependencies/webrtc-30326-1a68679-linux-arm.tar.gz",
 )
 
-new_http_archive(
+http_archive(
     name = "webrtc_rio",
     build_file = "@//debian:webrtc.BUILD",
     sha256 = "d86d3b030099b35ae5ea31c807fb4d0b0352598e79f1ea84877e5504e185faa8",