Bug 534862 - [releng] stop using jsr14 as a target

Class files built using the transitional jsr14 target are no longer
treated specially by modern Javas (7 and newer, which Eclipse
Platform now requires.) Support for jsr14 was never a documented and
supported option in the JDK and the target was finally removed from
javac in Java 8.

Change-Id: Ic6b3a7e4d69905e42b9e87dd42dc6fa8b95fbc05
Signed-off-by: Mat Booth <mat.booth@redhat.com>