Added/removed CI arches.

Added:
  - arm-unknown-linux-gnueabi
  - arm-unknown-linux-musleabi

Removed:
  - powerpc64-unknown-linux-gnu (not suppported by nix)
  - mips64el-unknown-linux-gnu (not suppported by nix)
  - mipsel-unknown-linux-gnu (not suppported by nix)

Author: berkowski

.travis.yml

@@ -46,9 +46,11 @@ matrix:
     - env: TARGET=mips64el-unknown-linux-gnuabi64
     - env: TARGET=mipsel-unknown-linux-gnu
     - env: TARGET=powerpc-unknown-linux-gnu
-    - env: TARGET=powerpc64-unknown-linux-gnu
+    # - env: TARGET=powerpc64-unknown-linux-gnu
     # - env: TARGET=powerpc64le-unknown-linux-gnu
     # - env: TARGET=s390x-unknown-linux-gnu
+    - env: TARGET=arm-unknown-linux-gnueabi
+    - env: TARGET=arm-unknown-linux-musleabi
 
     # Testing other channels
     - env: TARGET=x86_64-unknown-linux-gnu