travis: temporarily disable rustfmt ci check until rust-lang#4742 is resolved

Author: matthiaskrgr

.travis.yml

@@ -63,8 +63,9 @@ matrix:
       if: repo =~ /^rust-lang\/rust-clippy$/ AND branch IN (auto, try)
     - env: INTEGRATION=Geal/nom
       if: repo =~ /^rust-lang\/rust-clippy$/ AND branch IN (auto, try)
-    - env: INTEGRATION=rust-lang/rustfmt
-      if: repo =~ /^rust-lang\/rust-clippy$/ AND branch IN (auto, try)
+    # FIXME blocked on https://github.com/rust-lang/rust-clippy/issues/4742
+    #- env: INTEGRATION=rust-lang/rustfmt
+    #  if: repo =~ /^rust-lang\/rust-clippy$/ AND branch IN (auto, try)
     - env: INTEGRATION=hyperium/hyper
       if: repo =~ /^rust-lang\/rust-clippy$/ AND branch IN (auto, try)
     - env: INTEGRATION=bluss/rust-itertools