Stop using LOG macros in favor of RTC_ prefixed macros.

This CL has been generated with the following script:

for m in PLOG \
  LOG_TAG \
  LOG_GLEM \
  LOG_GLE_EX \
  LOG_GLE \
  LAST_SYSTEM_ERROR \
  LOG_ERRNO_EX \
  LOG_ERRNO \
  LOG_ERR_EX \
  LOG_ERR \
  LOG_V \
  LOG_F \
  LOG_T_F \
  LOG_E \
  LOG_T \
  LOG_CHECK_LEVEL_V \
  LOG_CHECK_LEVEL \
  LOG
do
  git grep -l $m | xargs sed -i "s,\b$m\b,RTC_$m,g"
done
git checkout rtc_base/logging.h
git cl format

Bug: webrtc:8452
Change-Id: I1a53ef3e0a5ef6e244e62b2e012b864914784600
Reviewed-on: https://webrtc-review.googlesource.com/21325
Reviewed-by: Niels Moller <nisse@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20617}
diff --git a/rtc_base/testclient_unittest.cc b/rtc_base/testclient_unittest.cc
index f3c8561..1d1d3f2 100644
--- a/rtc_base/testclient_unittest.cc
+++ b/rtc_base/testclient_unittest.cc
@@ -18,16 +18,16 @@
 
 using namespace rtc;
 
-#define MAYBE_SKIP_IPV4                    \
-  if (!HasIPv4Enabled()) {                 \
-    LOG(LS_INFO) << "No IPv4... skipping"; \
-    return;                                \
+#define MAYBE_SKIP_IPV4                        \
+  if (!HasIPv4Enabled()) {                     \
+    RTC_LOG(LS_INFO) << "No IPv4... skipping"; \
+    return;                                    \
   }
 
-#define MAYBE_SKIP_IPV6                    \
-  if (!HasIPv6Enabled()) {                 \
-    LOG(LS_INFO) << "No IPv6... skipping"; \
-    return;                                \
+#define MAYBE_SKIP_IPV6                        \
+  if (!HasIPv6Enabled()) {                     \
+    RTC_LOG(LS_INFO) << "No IPv6... skipping"; \
+    return;                                    \
   }
 
 void TestUdpInternal(const SocketAddress& loopback) {