Upgrade deprecated expressions in pom.xml for use in building effective models

We should upgrade these variables in pom.xml to remove this warning from the Jenkins CI build.

<===[JENKINS REMOTING CAPACITY]===>���channel started
Executing Maven: -B -f /home/jenkins/jenkins-slave/workspace/gora-trunk/trunk./pom.xml install
[WARNING]
[WARNING] Some problems were encountered while building the effective model for org.apache.gora:gora-core:jar:0.2-SNAPSHOT
[WARNING] The expression ${artifactId} is deprecated. Please use ${project.artifactId} instead.
[WARNING] The expression ${version} is deprecated. Please use ${project.version} instead.
[WARNING]
[WARNING] Some problems were encountered while building the effective model for org.apache.gora:gora-hbase:jar:0.2-SNAPSHOT
[WARNING] The expression ${artifactId} is deprecated. Please use ${project.artifactId} instead.
[WARNING] The expression ${version} is deprecated. Please use ${project.version} instead.
[WARNING]
[WARNING] Some problems were encountered while building the effective model for org.apache.gora:gora-cassandra:jar:0.2-SNAPSHOT
[WARNING] The expression ${artifactId} is deprecated. Please use ${project.artifactId} instead.
[WARNING] The expression ${version} is deprecated. Please use ${project.version} instead.
[WARNING]
[WARNING] Some problems were encountered while building the effective model for org.apache.gora:gora-sql:jar:0.2-SNAPSHOT
[WARNING] The expression ${artifactId} is deprecated. Please use ${project.artifactId} instead.
[INFO] [WARNING] The expression ${version} is deprecated. Please use ${project.version} instead.
Scanning for projects...[WARNING]

[WARNING] Some problems were encountered while building the effective model for org.apache.gora:gora-tutorial:jar:0.2-SNAPSHOT
[INFO] [WARNING] The expression ${artifactId} is deprecated. Please use ${project.artifactId} instead.
[WARNING] The expression ${version} is deprecated. Please use ${project.version} instead.
[WARNING]
[WARNING] Some problems were encountered while building the effective model for org.apache.gora:gora:pom:0.2-SNAPSHOT
[WARNING] The expression ${artifactId} is deprecated. Please use ${project.artifactId} instead.
[WARNING] The expression ${version} is deprecated. Please use ${project.version} instead.
[WARNING]
[WARNING] It is highly recommended to fix these problems because they threaten the stability of your build.
------------------------------------------------------------------------[WARNING]

[WARNING] For this reason, future Maven versions might no longer support building such malformed projects.
[INFO] Reactor Build Order:[WARNING]