handler: delete extra namespace alias

Delete extra namespace alias for phosphor::logging.

ested: Only ran unit-tests.
Change-Id: I2ed78bae5dba4c51d4d151d8c9e670ec04419e98
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/handler.cpp b/handler.cpp
index 2018ef6..93b3c21 100644
--- a/handler.cpp
+++ b/handler.cpp
@@ -158,8 +158,6 @@
 
 void Handler::psuResetDelay(std::uint32_t delay) const
 {
-    using namespace phosphor::logging;
-
     std::ofstream ofs;
     ofs.open(TIME_DELAY_FILENAME, std::ofstream::out);
     if (!ofs.good())