Revert "AMBARI-12134. Update poms to target 1.7 and 1.6 JREs. (Jonathan Halterman via yusaku)"

This reverts commit 04fb8fe35441f667dfeb16f8d2d04eddaaed9b4c due to unit test failures: https://builds.apache.org/job/Ambari-trunk-Commit/2995/

ambari-metrics/pom.xml

@@ -113,10 +113,6 @@
       <plugin>
         <artifactId>maven-compiler-plugin</artifactId>
         <version>3.0</version>
-        <configuration>
-          <source>1.6</source>
-          <target>1.6</target>
-        </configuration>
       </plugin>
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>

pom.xml

@@ -198,8 +198,8 @@
         <artifactId>maven-compiler-plugin</artifactId>
         <version>3.0</version>
         <configuration>
-            <source>1.7</source>
-            <target>1.7</target>
+            <source>1.6</source>
+            <target>1.6</target>
         </configuration>
       </plugin>
       <plugin>