scripted-diff: Replace error() with LogError()

This fixes the log output when -logsourcelocations is used.

Also, instead of 'ERROR:', the log will now say '[error]', like other
errors logged with LogError.

-BEGIN VERIFY SCRIPT-
 sed -i --regexp-extended 's!  error\("([^"]+)"!  LogError("\1\\n"!g' $( git grep -l '  error(' ./src/ )
-END VERIFY SCRIPT-

src/kernel/coinstats.cpp

@@ -134,7 +134,7 @@ static bool ComputeUTXOStats(CCoinsView* view, CCoinsStats& stats, T hash_obj, c
             outputs[key.n] = std::move(coin);
             stats.coins_count++;
         } else {
-            error("%s: unable to read value", __func__);
+            LogError("%s: unable to read value\n", __func__);
             return false;
         }
         pcursor->Next();