Allow musl build failure, blocked on travis-ci/apt-package-safelist#369…

… [appveyor skip]

.travis.yml

@@ -8,6 +8,7 @@ env:
     - PROJECT_NAME=ilc
 
 matrix:
+  fast_finish: true
   include:
     # Stable channel
     - os: linux
@@ -37,6 +38,7 @@ matrix:
       env: TARGET=x86_64-unknown-linux-gnu CHANNEL=stable
     - os: linux
       env: TARGET=x86_64-unknown-linux-musl CHANNEL=stable
+
     # Beta channel
     - os: linux
       env: TARGET=arm-unknown-linux-gnueabihf CHANNEL=beta
@@ -57,6 +59,7 @@ matrix:
       env: TARGET=x86_64-unknown-linux-gnu CHANNEL=beta
     - os: linux
       env: TARGET=x86_64-unknown-linux-musl CHANNEL=beta
+
     # Nightly channel
     - os: linux
       env: TARGET=arm-unknown-linux-gnueabihf CHANNEL=nightly
@@ -77,11 +80,18 @@ matrix:
       env: TARGET=x86_64-unknown-linux-gnu CHANNEL=nightly
     - os: linux
       env: TARGET=x86_64-unknown-linux-musl CHANNEL=nightly
+
   allow_failures:
     # NOTE This target appears to be broken on Rust 1.7.0
     # TODO You may want to remove this entry by the time Rust 1.8.0 is out
     - os: linux
       env: TARGET=arm-unknown-linux-gnueabihf CHANNEL=stable
+    - os: linux
+      env: TARGET=x86_64-unknown-linux-musl CHANNEL=stable
+    - os: linux
+      env: TARGET=x86_64-unknown-linux-musl CHANNEL=beta
+    - os: linux
+      env: TARGET=x86_64-unknown-linux-musl CHANNEL=nightly
 
 install:
   - export PATH="$PATH:~/multirust/bin"