Use iOS nightlies instead of a pinned version

.travis.yml

@@ -41,10 +41,10 @@ matrix:
       rust: nightly
     - os: osx
       env: TARGET=i386-apple-ios
-      rust: nightly-2015-09-08
+      rust: nightly
     - os: osx
       env: TARGET=x86_64-apple-ios
-      rust: nightly-2015-09-08
+      rust: nightly
     - os: linux
       env: TARGET=x86_64-rumprun-netbsd DOCKER=alexcrichton/rust-libc-rumprun:2015-11-27
       rust: nightly-2015-09-27

ci/run-travis.sh

@@ -108,7 +108,7 @@ cp ci/cargo-config .cargo/config
 # all others from the official distribution.
 if [ "$TRAVIS" = "true" ]; then
   case "$TARGET" in
-    *-apple-ios | *-rumprun-*)
+    *-rumprun-*)
       curl -s $EXTRA_TARGETS/$TARGET.tar.gz | \
        tar xzf - -C `rustc --print sysroot`/lib/rustlib
       ;;