Fix conflicts casued by protobuf version up to 25.0

Fix conflicts casued by protobuf version up to 25.0

Firstly, the protobuf has changed not to accept base c++ standard
below 14. Therefore, fixed it to C++14.
  /usr/include/absl/base/policy_checks.h:79:2: error: #error "C++ versions
   less than C++14 are not supported."
     79 | #error "C++ versions less than C++14 are not supported."

And the protobuf has removed SetLogHandler() as of the below commit at
version 22.0.
  Breaking change: Migrate to Abseil's logging library.
  (https://github.com/protocolbuffers/protobuf/commit/a9f1ea6)

Unfortunately, they have not offered any replacement function nor
guideline for alternative implementation of SetLogHandler() after
removing it. And the latest upstream nsjail has not fixed it too.
Therefore, removed the SetLogHandler() for now.

Change-Id: I2dbc35d499d71f63772d52e439738f14f460b6d5
Signed-off-by: Youngjae Cho <y0.cho@samsung.com>