Revert "Enforces minimum Java version 1.6 on the openid-connect-server project."

This reverts commit c007e69974.

openid-connect-server/pom.xml

@@ -26,18 +26,6 @@
     	<version>1.0.13-SNAPSHOT</version>
     	<relativePath>..</relativePath>
     </parent>
-    <build>
-        <plugins>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-compiler-plugin</artifactId>
-                <configuration>
-                    <source>${java-version}</source>
-                    <target>${java-version}</target>
-                </configuration>
-            </plugin>
-        </plugins>
-    </build>
     <dependencies>
 		<dependency>
 			<groupId>org.mitre</groupId>