Go back to installing only runtime libs in the slim images as intended

Author: gwynne

5.1/ubuntu/16.04/slim/Dockerfile

@@ -38,7 +38,7 @@ RUN set -e; \
     && gpg --batch --quiet --keyserver ha.pool.sks-keyservers.net --recv-keys "$SWIFT_SIGNING_KEY" \
     && gpg --batch --verify swift.tar.gz.sig swift.tar.gz \
     # - Unpack the toolchain, set libs permissions, and clean up.
-    && tar -xzf swift.tar.gz --directory / --strip-components=1 \
+    && tar -xzf swift.tar.gz --directory / --strip-components=1 $SWIFT_VERSION-$SWIFT_PLATFORM/usr/lib/swift/linux \
     && chmod -R o+r /usr/lib/swift \
     && rm -rf "$GNUPGHOME" swift.tar.gz.sig swift.tar.gz \
     && apt-get purge --auto-remove -y curl

5.1/ubuntu/18.04/slim/Dockerfile

@@ -39,7 +39,7 @@ RUN set -e; \
     && gpg --batch --quiet --keyserver ha.pool.sks-keyservers.net --recv-keys "$SWIFT_SIGNING_KEY" \
     && gpg --batch --verify swift.tar.gz.sig swift.tar.gz \
     # - Unpack the toolchain, set libs permissions, and clean up.
-    && tar -xzf swift.tar.gz --directory / --strip-components=1 \
+    && tar -xzf swift.tar.gz --directory / --strip-components=1 $SWIFT_VERSION-$SWIFT_PLATFORM/usr/lib/swift/linux \
     && chmod -R o+r /usr/lib/swift \
     && rm -rf "$GNUPGHOME" swift.tar.gz.sig swift.tar.gz \
     && apt-get purge --auto-remove -y curl gnupg