Manage cert only on master merge

.travis.yml

@@ -186,13 +186,13 @@ before_script:
     fi
     
   # Install signing cert into OSX keychain
-  - if [[ "${SPEC}" = "macx-clang" ]]; then
+  - if [[ "${SPEC}" = "macx-clang" && "${TRAVIS_PULL_REQUEST}" = "false" ]]; then
         export CODESIGN=codesign;
     fi
-  - if [[ "${SPEC}" = "macx-clang" ]]; then
+  - if [[ "${SPEC}" = "macx-clang" && "${TRAVIS_PULL_REQUEST}" = "false" ]]; then
         openssl aes-256-cbc -K $MAC_CERT_KEY -iv $MAC_CERT_IV -in deploy/MacCertificates.p12.enc -out deploy/MacCertificates.p12 -d;
     fi
-  - if [[ "${SPEC}" = "macx-clang" ]]; then
+  - if [[ "${SPEC}" = "macx-clang" && "${TRAVIS_PULL_REQUEST}" = "false" ]]; then
         source deploy/MacImportCert.sh;
     fi