Cleanup namespace ending comment

(This is a merge of http://go/wvgerrit/13400 from the Widevine CDM
repository.)

Replace "};  // namespace" with "}  // namespace":
ag -l --ignore-dir third_party "};  //" | \
while read f; do sed -r -i 's/\};  \/\//}  \/\//' $f ; done

Replace "// unnamed namespace" with "// namespace":
ag -l --ignore-dir third_party "unnamed namespace" | \
while read f; do sed -r -i 's/unnamed namespace/namespace/' $f ; done

Change-Id: I50ece9a127ce669f15cd532dfae1dd741338a075

libwvdrmengine/cdm/core/src/device_files.cpp

@@ -55,7 +55,7 @@ bool Hash(const std::string& data, std::string* hash) {
   return true;
 }
 
-}  // unnamed namespace
+}  // namespace
 
 namespace wvcdm {