Merge #11521: travis: move back to the minimal image

3d1c311 Revert "travis: filter out pyenv" (Cory Fields)
a86e81b travis: move back to the minimal image (Cory Fields)

Pull request description:

  The most recent update replaced the minimal image with a large one for the
  'generic' image. Switching back to 'minimal' should reduce dependencies and
  maybe speed us up some.

  It should also eliminiate the need for aa2e0f09e.

Tree-SHA512: 0e5f3e97e8d97add07ea228bc5ce1e51e8e069950dbb2871a7eece297995f20b671afdf1c68211ce404cba3ba393d61dfef30ed54d46d6805fde9388f6b4455e

.travis.yml

@@ -1,7 +1,7 @@
 sudo: required
 dist: trusty
 os: linux
-language: generic
+language: minimal
 cache:
   directories:
   - depends/built
@@ -40,7 +40,6 @@ env:
 
 before_install:
     - export PATH=$(echo $PATH | tr ':' "\n" | sed '/\/opt\/python/d' | tr "\n" ":" | sed "s|::|:|g")
-    - export PATH=$(echo $PATH | tr ':' "\n" | sed '/\/opt\/pyenv/d' | tr "\n" ":" | sed "s|::|:|g")
 install:
     - if [ -n "$DPKG_ADD_ARCH" ]; then sudo dpkg --add-architecture "$DPKG_ADD_ARCH" ; fi
     - if [ -n "$PACKAGES" ]; then travis_retry sudo apt-get update; fi