Let lock_guard deduce its template argument

No functional change, this is a cleanup.

With C++17, it's no longer necessary to specify the teplate argument
when it can be deduced from the types of constructor arguments. This
allows de-cluttering our locking statements.

To avoid typos, this patch was mechanically generated:

  perl -p -i -e 's/std::lock_guard<std::mutex>/std::lock_guard/g' \
    $(find . -name '*.cpp' -o -name '*.h')

Change-Id: Ibb15d9a6c5b1c861d81353e47d25474eb1d4c2df
diff --git a/server/NetdNativeService.cpp b/server/NetdNativeService.cpp
index c155ac1..ad6d6de 100644
--- a/server/NetdNativeService.cpp
+++ b/server/NetdNativeService.cpp
@@ -88,7 +88,7 @@
 
 #define NETD_LOCKING_RPC(permission, lock)                  \
     ENFORCE_PERMISSION(permission);                         \
-    std::lock_guard<std::mutex> _lock(lock);
+    std::lock_guard _lock(lock);
 
 #define NETD_BIG_LOCK_RPC(permission) NETD_LOCKING_RPC((permission), gBigNetdLock)