Dry up incremental-compiler dep on sbt-interface.

Testing Done:
Locally ran:
```console
$ OANTS_DEV=1 ./pants clean-all compile src/scala/::
```

CI went green here:
  https://travis-ci.org/pantsbuild/pants/builds/64450800

Bugs closed: 1602

Reviewed at https://rbcommons.com/s/twitter/r/2279/

3rdparty/jvm/com/typesafe/sbt/BUILD

@@ -8,9 +8,9 @@ jar_library(
   name='incremental-compiler',
   jars=[
     jar(org='com.typesafe.sbt', name='incremental-compiler', rev=SBT_REV, intransitive=True),
-    jar(org='com.typesafe.sbt', name='sbt-interface', rev=SBT_REV, intransitive=True)
   ],
   dependencies=[
+    '//:sbt-interface',
     '//:scala-compiler',
     '//:scala-library',
   ]