Kapt: compile annotation-processing artifact with target "1.6"

(cherry picked from commit 1391e59)

build.xml

@@ -790,7 +790,8 @@
     
     <target name="annotation-processing">
         <cleandir dir="${output}/classes/annotation-processing"/>
-        <javac2 destdir="${output}/classes/annotation-processing" debug="true" debuglevel="lines,vars,source" includeAntRuntime="false">
+        <javac2 destdir="${output}/classes/annotation-processing" debug="true" debuglevel="lines,vars,source" 
+                includeAntRuntime="false" source="${java.target}" target="${java.target}">
             <withKotlin modulename="annotation-processing">
                 <compilerarg value="-version"/>
             </withKotlin>

libraries/tools/kotlin-annotation-processing/pom.xml

@@ -160,6 +160,10 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>1.6</source>
+                    <target>1.6</target>
+                </configuration>
             </plugin>
             <plugin>
                 <artifactId>maven-failsafe-plugin</artifactId>