Reduce source/target from 1.7 to 1.6

[glassfishrobot]

Currently the el api and impl are set to source/target 1.7

However, there are no functional requirement or features of the 1.7 JRE used.

The only current barrier is with tests which fail when set to 1.6. However, when skipping tests, el compiles quite fine.

This has a transitive cost of imposing 1.7 on JSP also.

[glassfishrobot]

Reported by rotty

[glassfishrobot]

rotty said: See JSP-43

[glassfishrobot]

rotty said: After further discussion with colleagues we realized there is no need for this.

the issue can be resolved "won't fix"

[glassfishrobot]

This issue was imported from java.net JIRA EL_SPEC-20