travis.yml: update environment

Update osx used images to osx-10.2
Update linux to Ubuntu 18.04
Update ASIO to 1.13.0
Update OpenSSL to 1.0.2s
Compile with -std=c++14 flag

while at it, fix a script syntax error.

Signed-off-by: Antonio Quartulli <antonio@openvpn.net>

.travis.yml

@@ -1,19 +1,17 @@
-dist: trusty
-
+dist: bionic
 os: linux
-
 language: cpp
 
 env:
   global:
     - secure: "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"
     - PREFIX="${HOME}/opt"
-    - ASIO_VERSION="862aed305dcf91387535519c9549c17630339a12"
+    - ASIO_VERSION="90f32660cd503494b3707840cfbd5434d8e9dabe"
     - LZ4_VERSION="1.8.3"
     - MBEDTLS_VERSION="2.7.5"
     - MBEDTLS_CFLAGS="-I${PREFIX}/include"
     - MBEDTLS_LIBS="-lmbedtls -lmbedx509 -lmbedcrypto"
-    - OPENSSL_VERSION="1.0.2l"
+    - OPENSSL_VERSION="1.0.2s"
     - OPENSSL_CFLAGS="-I${PREFIX}/include"
     - OPENSSL_LIBS="-lssl -lcrypto"
     - COVERITY_BRANCH="master"
@@ -22,9 +20,11 @@ matrix:
   include:
     - env: SSLLIB="openssl"
       os: osx
+      osx_image: xcode10.2
       compiler: clang
     - env: SSLLIB="mbedtls"
       os: osx
+      osx_image: xcode10.2
       compiler: clang
     - env: SSLLIB="openssl" RUN_COVERITY_SCAN="1"
       os: linux

.travis/build-check.sh

@@ -25,11 +25,11 @@ else
 fi
 
 LIBS="${SSL_LIBS} -llz4"
-CXXFLAGS="-O3 -std=c++11 -Wall -pthread \
+CXXFLAGS="-O3 -std=c++14 -Wall -pthread \
           -DOPENVPN_SHOW_SESSION_TOKEN -DHAVE_LZ4 \
           -DUSE_ASIO -DASIO_STANDALONE -DASIO_NO_DEPRECATED ${SSL_CFLAGS}"
 
-if [[ "${CC}" == "gcc"* ]]; then
+if [ "${CC}" = "gcc" ]; then
     CXXFLAGS="${CXXFLAGS} -fwhole-program -flto=4"
 fi