Remove codecov from travis script

Following codecov security breach, removing codecov.

.travis.yml

@@ -50,8 +50,6 @@ matrix:
 #      env: GPAC_CONFIGURE_OPTIONS="--enable-mem-track" GPAC_CONFIGURE_ECFLAGS="" DOINSTALL="sudo make install" DOTRAVIS="" AUDIODEV=null
 script:
   - ./configure --extra-cflags=''"$GPAC_CONFIGURE_ECFLAGS"'' $GPAC_CONFIGURE_OPTIONS && make && $DOINSTALL && ( if [ -n "$DOTRAVIS" ]; then xvfb-run -e /dev/stdout --auto-servernum --server-num=1 --server-args="-screen 0 1024x768x24" $DOTRAVIS ; fi )
-after_success:
-  - if [ "$TRAVIS_OS_NAME" == "linux" ]; then bash <(curl -s https://codecov.io/bash) ; fi
 
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