[Travis] Fix build with Clang 7

.travis.yml

@@ -48,11 +48,11 @@ matrix:
 
     # Clang 5.0
     - env: UNIT_TESTS=true COMPILER=clang++-5.0 BOOST_VERSION=default ENABLE_MEMCHECK=true
-      addons: &defaults { apt: { packages: ["clang-5.0", "valgrind"], sources: ["ubuntu-toolchain-r-test", "llvm-toolchain-trusty-5.0"] } }
+      addons: { apt: { packages: ["clang-5.0", "valgrind"], sources: ["ubuntu-toolchain-r-test", "llvm-toolchain-trusty-5.0"] } }
 
     # Clang 6.0
     - env: UNIT_TESTS=true COMPILER=clang++-6.0 BOOST_VERSION=default ENABLE_MEMCHECK=true
-      addons: &defaults { apt: { packages: ["clang-6.0", "valgrind"], sources: ["ubuntu-toolchain-r-test", "llvm-toolchain-trusty-6.0"] } }
+      addons: { apt: { packages: ["clang-6.0", "valgrind"], sources: ["ubuntu-toolchain-r-test", "llvm-toolchain-trusty-6.0"] } }
 
     # Clang 7.0
     - env: UNIT_TESTS=true COMPILER=clang++-7 BOOST_VERSION=default ENABLE_MEMCHECK=true
@@ -177,7 +177,7 @@ install:
   ############################################################################
   # Setup default versions and override CXX set by Travis if needed
   ############################################################################
-  - if [[ "${COMPILER}" == "default" ]]; then COMPILER=clang++-7.0; fi
+  - if [[ "${COMPILER}" == "default" ]]; then COMPILER=clang++-7; fi
   - if [[ "${BOOST_VERSION}" == "default" ]]; then BOOST_VERSION=1.66.0; fi
 
   - if [[ "${COMPILER}" != "" ]]; then export CXX=${COMPILER}; fi
@@ -240,7 +240,7 @@ install:
       elif [[ "${CXX}" == "clang++-4.0" ]]; then LLVM_VERSION="4.0.1";
       elif [[ "${CXX}" == "clang++-5.0" ]]; then LLVM_VERSION="5.0.2";
       elif [[ "${CXX}" == "clang++-6.0" ]]; then LLVM_VERSION="6.0.1";
-      elif [[ "${CXX}" == "clang++-7.0" ]]; then LLVM_VERSION="7.0.1";
+      elif [[ "${CXX}" == "clang++-7" ]];   then LLVM_VERSION="7.0.1";
       fi
 
       LLVM_URL="http://llvm.org/releases/${LLVM_VERSION}/llvm-${LLVM_VERSION}.src.tar.xz"