use latest travis syntax

Signed-off-by: Jay Lee <[email protected]>

.travis.yml

@@ -3,11 +3,6 @@ rust: nightly
 services: docker
 
 jobs:
-  allow_failures:
-    - if: branch != master
-      env: JEMALLOC_SYS_VERIFY_CONFIGURE=1
-
-matrix:
   include:
     # Linux
     - name: "aarch64-unknown-linux-gnu"
@@ -129,7 +124,7 @@ matrix:
       deploy:
         provider: script
         script: curl -LsSf https://git.io/fhJ8n | rustc - && (cd target/doc && ../../rust_out)
-        skip_cleanup: true
+        cleanup: true
         on:
           branch: master
     - name: "rustfmt"
@@ -153,6 +148,9 @@ matrix:
     - name: "Shellcheck"
       install: true
       script: shellcheck ci/*.sh
+  allow_failures:
+    - if: env(TRAVIS_PULL_REQUEST) != "false"
+      env: JEMALLOC_SYS_VERIFY_CONFIGURE=1
 
 install: rustup target add ${TARGET}
 script: sh ci/run.sh