scripted-diff: LogPrintLevel(*,BCLog::Level::*,*) -> LogError()/LogWarning()

This is a minimal behavior change and changes log output from:

  [net:error] Something bad happened
  [net:warning] Something problematic happened

to either

  [error] Something bad happened
  [warning] Something problematic happened

or, when -loglevelalways=1 is enabled:

  [all:error] Something bad happened
  [all:warning] Something problematic happened

Such a behavior change is desired, because all warning and error logs
are written in the same style in the source code and they are logged in
the same format for log consumers.

-BEGIN VERIFY SCRIPT-

 sed --regexp-extended --in-place \
   's/LogPrintLevel\((BCLog::[^,]*), BCLog::Level::(Error|Warning), */Log\2(/g' \
   $( git grep -l LogPrintLevel ':(exclude)src/test/logging_tests.cpp' )

-END VERIFY SCRIPT-

src/validation.cpp

@@ -2798,7 +2798,7 @@ bool Chainstate::FlushStateToDisk(
                 // TODO: Handle return error, or add detailed comment why it is
                 // safe to not return an error upon failure.
                 if (!m_blockman.FlushChainstateBlockFile(m_chain.Height())) {
-                    LogPrintLevel(BCLog::VALIDATION, BCLog::Level::Warning, "%s: Failed to flush block file.\n", __func__);
+                    LogWarning("%s: Failed to flush block file.\n", __func__);
                 }
             }