Point to the new maven-central https endpoint.
This was brought to my attention by aurora threads and the announce was this weekend here: http://central.stage.sonatype.org/articles/2014/Aug/03/https-support-launching-now/

Also kill an unused resolver copied over from twitter/commons.

Testing Done:
$ rm -rf ~/.pants.d/tools/
$ PANTS_DEV=1 ./pants goal clean-all
$ PANTS_IVY_CACHE_DIR=/tmp/ivy2 PANTS_DEV=1 ./pants goal test {src,tests}/{scala,java}/::
...
               Executing goals in phases: bootstrap -> imports -> gen -> check-exclusives -> resolve -> compile -> resources -> test
13:10:18 00:17   [bootstrap]
13:10:18 00:17     [bootstrap-jvm-tools]
13:10:18 00:17   [imports]
13:10:18 00:17     [ivy-imports] INFO]
Downloading https://repo1.maven.org/maven2/org/apache/ivy/ivy/2.3.0/ivy-2.3.0.jar
 INFO] Starting new HTTPS connection (1): repo1.maven.org
100% .................................................. 1193 KB 6.273s
 INFO] sha1: c5ebf1c253ad4959a29f4acfe696ee48cdd9f473
...
13:20:11 10:10   [test]
13:20:11 10:10     [pytest]
13:20:11 10:10     [junit]
13:20:11 10:10       [bootstrap-junit]
13:20:40 10:39       [run]
                     ..........
                     Time: 0.177

                     OK (10 tests)

13:20:41 10:40     [specs]
               Waiting for background workers to finish.
               SUCCESS

$ find /tmp/ivy2 -name "ivydata-*.properties" | xargs grep location | cut -d= -f2 | cut -d/ -f-4 | sort | uniq -c
     15 http\://maven.twttr.com/com
      3 http\://maven.twttr.com/org
    225 https\://repo1.maven.org/maven2

Bugs closed: 438

Reviewed at https://rbcommons.com/s/twitter/r/824/