Tvheadend

When trying to load or create a v4l service, tvheadend crashes in transport_make_nicename.

The attached patch fixes this.

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0xb32fcb70 (LWP 3308)]
0x0806c102 in v4l_transport_setsourceinfo (t=0x8518ea8, si=0xb32fb64c)
at /home/stephane/tmp/tvheadend/src/v4l.c:309
309 si->si_adapter = strdup(t->tht_v4l_adapter->va_displayname);
(gdb) where
#0 0x0806c102 in v4l_transport_setsourceinfo (t=0x8518ea8, si=0xb32fb64c)
at /home/stephane/tmp/tvheadend/src/v4l.c:309
#1 0x0805d451 in transport_make_nicename (t=0x8518ea8)
at /home/stephane/tmp/tvheadend/src/transports.c:560
#2 0x0806c40f in v4l_transport_find (va=0x84d9388, id=0x0, create=1)
at /home/stephane/tmp/tvheadend/src/v4l.c:359
#3 0x08089b58 in extjs_v4lservices (hc=0xb32fc2cc,
remain=0xb32fbe8f "_dev_video0", opaque=0x0)
at /home/stephane/tmp/tvheadend/src/webui/extjs.c:2012
#4 0x080532b9 in http_exec (hc=0xb32fc2cc, hp=0x85481e8,
remain=0xb32fbe8f "_dev_video0")
at /home/stephane/tmp/tvheadend/src/http.c:327
#5 0x0805369b in http_cmd_post (hc=0xb32fc2cc, spill=<value optimized out>)
at /home/stephane/tmp/tvheadend/src/http.c:417
#6 http_process_request (hc=0xb32fc2cc, spill=<value optimized out>)
at /home/stephane/tmp/tvheadend/src/http.c:435
#7 process_request (hc=0xb32fc2cc, spill=<value optimized out>)
at /home/stephane/tmp/tvheadend/src/http.c:500
#8 0x0805390e in http_serve_requests (hc=0xb32fc2cc, spill=0xb32fc330)
at /home/stephane/tmp/tvheadend/src/http.c:725
#9 0x08053a04 in http_serve (fd=16, opaque=0x0, peer=0x85cfd3c,
self=0x85cfd4c) at /home/stephane/tmp/tvheadend/src/http.c:768
#10 0x08052051 in tcp_server_start (aux=0x85cfd30)
at /home/stephane/tmp/tvheadend/src/tcp.c:391
#11 0x00b2680e in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#12 0x004187ee in clone () from /lib/tls/i686/cmov/libc.so.6