[SPARK-24895] Remove spotbugs plugin

## What changes were proposed in this pull request?

Spotbugs maven plugin was a recently added plugin before 2.4.0 snapshot artifacts were broken.  To ensure it does not affect the maven deploy plugin, this change removes it.

## How was this patch tested?

Local build was ran, but this patch will be actually tested by monitoring the apache repo artifacts and making sure metadata is correctly uploaded after this job is ran: https://amplab.cs.berkeley.edu/jenkins/view/Spark%20Packaging/job/spark-master-maven-snapshots/

Author: Eric Chang <[email protected]>

Closes apache#21865 from ericfchang/SPARK-24895.

Author: ericfchang

pom.xml

@@ -2610,28 +2610,6 @@
           </execution>
         </executions>
       </plugin>
-      <plugin>
-        <groupId>com.github.spotbugs</groupId>
-        <artifactId>spotbugs-maven-plugin</artifactId>
-        <version>3.1.3</version>
-        <configuration>
-          <classFilesDirectory>${basedir}/target/scala-${scala.binary.version}/classes</classFilesDirectory>
-          <testClassFilesDirectory>${basedir}/target/scala-${scala.binary.version}/test-classes</testClassFilesDirectory>
-          <effort>Max</effort>
-          <threshold>Low</threshold>
-          <xmlOutput>true</xmlOutput>
-          <visitors>FindPuzzlers</visitors>
-          <fork>true</fork>
-        </configuration>
-        <executions>
-          <execution>
-            <goals>
-              <goal>check</goal>
-            </goals>
-            <phase>compile</phase>
-          </execution>
-        </executions>
-      </plugin>
     </plugins>
   </build>