Fix release builds when multlple Go version builds are used

©! I, Hugo Landau <hlandau@devever.net>, hereby licence these changes under the
©! licence with SHA256 hash
©! fd80a26fbb3f644af1fa994134446702932968519797227e07a1368dea80f0bc.

.travis.yml

@@ -25,3 +25,5 @@ after_success:
 env:
   # GITHUB_TOKEN for automatic releases
   - secure: "at1oJs7ib7glx3W+zk+OkT041LdknVXirIhN403CIihVUrlOhODY7yCTgvF4Rk0jYBJiT35Q2qxpgfWF2qGnsNsQmjG3ydDWQDCepDc/CgXfLyoiSTJK5vTK72dYWTVsBTycXbj1CbSy2X2ah/KWjc4RcgZ67ER7mDpRU5nFeow="
+  # Set this to the Go version to use for releases (must appear in version list above).
+  - RELEASE_GO_VERSION="1.8"

.travis/after_success

@@ -11,6 +11,11 @@ if [ -z "$GITHUB_TOKEN" ]; then
   return 0
 fi
 
+if [[ "${TRAVIS_GO_VERSION}." != "${RELEASE_GO_VERSION}."* ]]; then
+  echo "Travis Go version ($TRAVIS_GO_VERSION) is not the releasing version ($RELEASE_GO_VERSION), not releasing."
+  return 0
+fi
+
 # Make archives.
 echo Archiving releases...
 SRC_DIR="$(pwd)"