capture() can, in some cases, return FALSE when the capture succeeds;

capture() can, in some cases, return FALSE when the capture succeeds;
back out the change to check its return value until we fix that.

Also back out the test suite changes to look for an error exit for
invalid capture filters and interfaces.

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@33029 f5534014-38df-0310-8fa8-9805f1628bb7