Travis: revert the hack for transient build failures.

.travis.yml

@@ -4,6 +4,7 @@ os:
   - osx
 sudo: required
 dist: trusty
+osx_image: xcode8.2
 install:
   - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then ./.travis/install-debian.sh; fi
   - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then ./.travis/install-macos.sh; fi

.travis/build-macos.sh

@@ -5,16 +5,4 @@ if echo $TRAVIS_TAG | grep ^v; then BUILD_TYPE=RelWithDebInfo; else BUILD_TYPE=D
 mkdir build
 cd build
 cmake -DCMAKE_OSX_DEPLOYMENT_TARGET=10.7 -DCMAKE_BUILD_TYPE=$BUILD_TYPE ..
-if ! make VERBOSE=1; then
-  echo "Sigh, transient build failure. Retrying..."
-  if ! make VERBOSE=1; then
-    echo "Another transient build failure. Retrying..."
-    if ! make VERBOSE=1; then
-      echo "I can't believe how deep the Travis brokenness goes. Retrying..."
-      if ! make VERBOSE=1; then
-        echo "Okay, this is probably an actual bug."
-        exit 1
-      fi
-    fi
-  fi
-fi
+make VERBOSE=1