[travis-ci][coverity] Try a different approach to trigger coverity scan on auto-build branch.

Author: c-lipka

.travis.yml

@@ -47,7 +47,11 @@ addons:
     notification_email: [email protected]
     build_command_prepend: "unix/prebuild.sh ; ./configure"
     build_command: "make"
-    branch_pattern: (coverity_scan|autobuild*)
+    # Instead of using pattern matching to choose which branches to run Coverity Scan on
+    # (which turns out more difficult than expected), we simply use different .travis.yml files.
+    # We need to do that anyway, because normally we also run osx/clang, which doesn't sit well
+    # with Covertiy Scan.
+    branch_pattern: "*"
 
 script:
 - true