Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

devd: correct two warnings

- catching a polymorphic type by value
- "output between 16 and 95 bytes into a destination of size 80"

Fix an intermittent bug in sbin/devd/client_test.stream

In case where the two events were being received in separate reads, the
event buffer was being null-terminated at the wrong offset.

Also, factored out some common code between the tests, and fixed a comment.

Submitted by: will
MFC after: 3 days
Sponsored by: Spectra Logic Corp

Misc fixes suggested by Coverity.

sbin/devd/tests/client_test.c
* In the event that popen fails, don't dereference its return value.
* Fix array overwrite in the stream and seqpacket tests.
* Close sockets at the end of successful ATF tests.

Reported by: Coverity scan
CID: 1232019, 1232020, 1232029, 1232030
MFC after: 1 week
Sponsored by: Spectra Logic

Remove bogus ; at the end of the if condition in order to unbreak gcc builds
after r270004.

MFC after: 4 days
X-MFX with: r270004