Stop testing on Java 7

It reached its EOL years ago and almost no one uses it these days.

Author: bbatsov

.travis.yml

@@ -18,7 +18,6 @@ env:
     - secure: "bCp4gU7XgeqLnqKwEpJarnKPbGljHyLE2rZnub4mEHD8kcvh6LoEkG/2QCtnSETj8zrQJwyMuEDGUwPgjmzQ/aEn6UiIYmv7ka6QnLBxOxhqQTbDtG7HssfkeT5b67LgOyQX7ejK88vnmH+OeWXM7kOOvUwVy5BVgsYyr2f1cGU="
     - secure: "D2Ie7dUZ9nQOIWtkRl2XWZeijSL8expUXP3GziSqQV1scJzwexxnUsRvWOkc2YU8+6IIGz9tcyt9RrEFUVF31VZgRSHh8P5rGGCzI2l99djKhYFfSErElwgoAJZFtOzougZK66/Gtb5uDo5L/wlKHkl4st3miqm+mEvfJITDjRQ="
 jdk:
-  - openjdk7
   - oraclejdk8
   - oraclejdk9
 stages:
@@ -66,13 +65,6 @@ jobs:
       env: TARGET=deploy
       jdk: oraclejdk8
 
-  exclude:
-    # CLJS-1.9 doesn't build on JDK7. This is because of a dependency on the
-    # google/closure-compiler which requires JDK8 or higher.
-    # https://github.com/google/closure-compiler/wiki/Releases#september-10-2017-v20170910
-    - env: VERSION=1.9 TARGET=test-cljs
-      jdk: openjdk7
-
   fast_finish: true      # don't wait for allowed failures before build finish
   allow_failures:
     - env: VERSION=master TARGET=test-clj