HADOOP-11030. Define a variable jackson.version instead of using constant at multiple places. (Juan Yu via kasha)

(cherry picked from commit 9ad413b19d98352e4ae848a945ab1f72ababa576)

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -152,6 +152,9 @@ Release 2.6.0 - UNRELEASED
     HADOOP-11021. Configurable replication factor in the hadoop archive
     command. (Zhe Zhang via wang)
 
+    HADOOP-11030. Define a variable jackson.version instead of using constant 
+    at multiple places. (Juan Yu via kasha)
+
   OPTIMIZATIONS
 
     HADOOP-10838. Byte array native checksumming. (James Thomas via todd)

hadoop-project/pom.xml

@@ -61,6 +61,9 @@
     <!-- jersey version -->
     <jersey.version>1.9</jersey.version>
 
+    <!-- jackson version -->
+    <jackson.version>1.9.13</jackson.version>
+
     <!-- ProtocolBuffer version, used to verify the protoc version and -->
     <!-- define the protobuf JAR version                               -->
     <protobuf.version>2.5.0</protobuf.version>
@@ -660,22 +663,22 @@
       <dependency>
         <groupId>org.codehaus.jackson</groupId>
         <artifactId>jackson-mapper-asl</artifactId>
-        <version>1.9.13</version>
+        <version>${jackson.version}</version>
       </dependency>
       <dependency>
         <groupId>org.codehaus.jackson</groupId>
         <artifactId>jackson-core-asl</artifactId>
-        <version>1.9.13</version>
+        <version>${jackson.version}</version>
       </dependency>
       <dependency>
         <groupId>org.codehaus.jackson</groupId>
         <artifactId>jackson-jaxrs</artifactId>
-        <version>1.9.13</version>
+        <version>${jackson.version}</version>
       </dependency>
       <dependency>
         <groupId>org.codehaus.jackson</groupId>
         <artifactId>jackson-xc</artifactId>
-        <version>1.9.13</version>
+        <version>${jackson.version}</version>
       </dependency>
       <dependency>
         <groupId>org.mockito</groupId>