Fix build break due to updated travis build vm.

.travis.yml

@@ -1,11 +1,12 @@
 sudo: required
-group: deprecated-2017Q3
-language: scala
-scala:
-  - 2.11.8
+os: linux
+dist: bionic
+jdk: openjdk11
+
 services:
   - docker
 
+
 notifications:
   email: false
   webhooks:
@@ -14,6 +15,8 @@ notifications:
       secure: 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
 
 before_install:
+  # Refresh built in certificates.
+  - sudo update-ca-certificates --fresh
   - 'if [ "$TRAVIS_PULL_REQUEST" = "false" ]; then openssl aes-256-cbc -K "$encrypted_DF18CF3F552A_key" -iv "$encrypted_DF18CF3F552A_iv" -in tests/credentials.json.enc -out tests/credentials.json -d; fi'
   - "./tools/travis/setup.sh"
 install: true

swift4.2/Dockerfile

@@ -65,7 +65,9 @@ ENV SWIFT_PLATFORM=$SWIFT_PLATFORM \
     SWIFT_VERSION=$SWIFT_VERSION
 
 # Download GPG keys, signature and Swift package, then unpack, cleanup and execute permissions for foundation libs.
-RUN SWIFT_URL=https://swift.org/builds/$SWIFT_BRANCH/$(echo "$SWIFT_PLATFORM" | tr -d .)/$SWIFT_VERSION/$SWIFT_VERSION-$SWIFT_PLATFORM.tar.gz \
+# https://download.swift.org/swift-4.2.4-release/ubuntu1804/swift-4.2.4-RELEASE/swift-4.2.4-RELEASE-ubuntu18.04.tar.gz
+RUN set -x \
+    && SWIFT_URL=https://download.swift.org/$SWIFT_BRANCH/$(echo "$SWIFT_PLATFORM" | tr -d .)/$SWIFT_VERSION/$SWIFT_VERSION-$SWIFT_PLATFORM.tar.gz \
     && curl -fSsL $SWIFT_URL -o swift.tar.gz \
     && curl -fSsL $SWIFT_URL.sig -o swift.tar.gz.sig \
     && export GNUPGHOME="$(mktemp -d)" \
@@ -89,7 +91,7 @@ RUN SWIFT_URL=https://swift.org/builds/$SWIFT_BRANCH/$(echo "$SWIFT_PLATFORM" |
         done \
     && gpg --batch --verify --quiet swift.tar.gz.sig swift.tar.gz \
     && tar -xzf swift.tar.gz --directory / --strip-components=1 \
-    && rm -r "$GNUPGHOME" swift.tar.gz.sig swift.tar.gz \
+    && rm -r "$GNUPGHOME" swift.tar.gz.sig swift.tar.gz || true \
     && chmod -R o+r /usr/lib/swift \
     # Print Installed Swift Version
     && swift --version