Revert "Enable automatic coverity coverage"

This reverts commit eb6365a.

The travis stuff isn't supposed to work that way; also, we're doing
weekly coverity builds with buildbot now, so it's less relevant.

.travis.yml

@@ -9,15 +9,3 @@ install:
   - sudo apt-get install docbook-utils
   - automake --version
 script: ./autogen.sh && ./configure && make && make check
-env:
-  global:
-   - secure: "cDahKVwhMIaj2nzcZOfgmzrpnF6JW96adc+DmA+iVhvklB+SgQ72rjzKLVb6vDttArwqLIF4/z1iCkdm6hI5n/osEyDqsC0LI+8MTXp2v3niXjHjno7i7zRvSMw1+e3x7QOu67TWJEcxx97JRHPmPcqKBQNqAZCri3ZUGE+tNUE="
-addons:
-  coverity_scan:
-    project:
-      name: "yoe/nbd"
-      description: "Network Block Device"
-    notification_email: w@uter.be
-    build_command_prepend:
-    build_command:
-    branch_pattern: coverity_scan