fixup gdb lines in .travis.yml

they should use -q and run in batch mode

.travis.yml

@@ -44,9 +44,9 @@ after_failure:
     - echo "$TEST_ERROR_CODE"
     - if [ "$TEST_ERROR_CODE" = 200 ]; then echo -e "\n***\n*\n* Encountered a segfault in the c++ unit test executable, attempting to get a backtrace in the remaining time...\n*\n***\n"; fi
     - if [ "$TEST_ERROR_CODE" = 200 ]; then time sudo apt-get install -qq gdb; fi
-    - if [ "$TEST_ERROR_CODE" = 200 ]; then time gdb --eval-command=start --eval-command=continue --eval-command=bt --eval-command=quit --args ./test; fi
+    - if [ "$TEST_ERROR_CODE" = 200 ]; then time gdb -q -batch -ex start -ex continue -ex bt -ex quit --args ./test; fi
     - if [ "$TEST_ERROR_CODE" = 200 ]; then time scons build=debug extra_flags_debug="$EXTRA_FLAGS_RELEASE" test; fi
-    - if [ "$TEST_ERROR_CODE" = 200 ]; then time gdb --eval-command=start --eval-command=continue --eval-command=bt --eval-command=quit --args ./test-debug; fi
+    - if [ "$TEST_ERROR_CODE" = 200 ]; then time gdb -q -batch -ex start -ex continue -ex bt -ex quit --args ./test-debug; fi
 notifications:
     email: false
     irc: