Remove rumprun target from .travis.yml

This patch removes the x86_64-rumprun-netbsd triple from Travis CI.

Author: jabedude

.travis.yml

@@ -69,7 +69,6 @@ matrix:
            RUSTFLAGS=-Clink-arg=-mios-simulator-version-min=7.0
       before_install:
         rustc ./ci/ios/deploy_and_run_on_ios_simulator.rs -o $HOME/runtest
-    - env: TARGET=x86_64-rumprun-netbsd
     - env: TARGET=powerpc-unknown-linux-gnu
     - env: TARGET=powerpc64-unknown-linux-gnu
     - env: TARGET=powerpc64le-unknown-linux-gnu