HADOOP-19248. Protobuf code generate and replace should happen together (#6975)

Contributed by Cheng Pan

hadoop-project/pom.xml

@@ -2287,7 +2287,7 @@
           <executions>
             <execution>
               <id>replace-generated-sources</id>
-              <phase>process-sources</phase>
+              <phase>generate-sources</phase>
               <goals>
                 <goal>replace</goal>
               </goals>
@@ -2307,7 +2307,7 @@
             </execution>
             <execution>
               <id>replace-generated-test-sources</id>
-              <phase>process-test-resources</phase>
+              <phase>generate-test-resources</phase>
               <goals>
                 <goal>replace</goal>
               </goals>
@@ -2327,7 +2327,7 @@
             </execution>
             <execution>
               <id>replace-sources</id>
-              <phase>process-sources</phase>
+              <phase>generate-sources</phase>
               <goals>
                 <goal>replace</goal>
               </goals>
@@ -2347,7 +2347,7 @@
             </execution>
             <execution>
               <id>replace-test-sources</id>
-              <phase>process-test-sources</phase>
+              <phase>generate-test-sources</phase>
               <goals>
                 <goal>replace</goal>
               </goals>