HADOOP-16220. Add findbugs ignores for unjustified issues during update to guava to 27.0-jre in hadoop-project

This closes #665

Signed-off-by: Akira Ajisaka <aajisaka@apache.org>

hadoop-hdfs-project/hadoop-hdfs/dev-support/findbugsExcludeFile.xml

@@ -185,6 +185,28 @@
        <Bug pattern="OS_OPEN_STREAM" />
      </Match>
 
+     <!-- guava 27.0 update: @Nullable is not detected, however it's there -->
+     <Match>
+       <Class name="org.apache.hadoop.hdfs.qjournal.server.Journal" />
+       <Method name="persistPaxosData" />
+       <Bug pattern="NP_NULL_PARAM_DEREF" />
+     </Match>
+
+
+     <!-- guava 27.0 update: @Nullable is not detected, however it's there -->
+     <Match>
+       <Class name="org.apache.hadoop.hdfs.qjournal.server.JournalNode" />
+       <Method name="getLogDir" />
+       <Bug pattern="NP_NULL_PARAM_DEREF" />
+     </Match>
+
+      <!-- guava 27.0 update: redundant nullcheck (assert for not null) -->
+      <Match>
+        <Class name="org.apache.hadoop.hdfs.qjournal.server.JournalNode" />
+        <Method name="getLogDir" />
+        <Bug pattern="RCN_REDUNDANT_NULLCHECK_WOULD_HAVE_BEEN_A_NPE" />
+      </Match>
+
      <!-- Don't complain about LocalDatanodeInfo's anonymous class -->
      <Match>
        <Class name="org.apache.hadoop.hdfs.client.impl.BlockReaderLocal$LocalDatanodeInfo$1" />