Tweaking log calls a bit.

-) Introducing gpr_vlog so to spare a few vsprintf later (at least one for now)
-) Renaming statistics/log.* to statistics/census_log.* to avoid collisions.
	Change on 2014/12/12 by nnoble <nnoble@google.com>
-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=81995756
diff --git a/build.json b/build.json
index e615826..b4dc9b6 100644
--- a/build.json
+++ b/build.json
@@ -137,7 +137,7 @@
         "src/core/statistics/census_rpc_stats.c",
         "src/core/statistics/census_tracing.c",
         "src/core/statistics/hash_table.c",
-        "src/core/statistics/log.c",
+        "src/core/statistics/census_log.c",
         "src/core/statistics/window_stats.c",
         "src/core/surface/byte_buffer.c",
         "src/core/surface/byte_buffer_reader.c",
@@ -228,7 +228,7 @@
         "src/core/statistics/census_interface.h",
         "src/core/statistics/census_rpc_stats.h",
         "src/core/statistics/hash_table.h",
-        "src/core/statistics/log.h",
+        "src/core/statistics/census_log.h",
         "src/core/statistics/window_stats.h",
         "src/core/surface/call.h",
         "src/core/surface/channel.h",