dahdi: Fix compilation with ancient DAHDI

We had an #ifndef DAHDI_SPECIFY clause which clearly wouldn't compile
as it used a wrong variable name.  Apparently nobody is building against
such ancient DAHDI for a long time...

Change-Id: Ib18343c0914ef25e673b930fa86b2dec6129065d
---
M src/input/dahdi.c
1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/input/dahdi.c b/src/input/dahdi.c
index adae121..efed38d 100644
--- a/src/input/dahdi.c
+++ b/src/input/dahdi.c
@@ -600,7 +600,7 @@
 	char name[32];
 #ifndef DAHDI_SPECIFY
 	char openstr[128];
-	snprintf(openstr, sizeof(openstr), "/dev/dahdi/%d", dev_nr);
+	snprintf(openstr, sizeof(openstr), "/dev/dahdi/%d", dahdi_chan_nr);
 #else
 	const char *openstr = "/dev/dahdi/channel";
 #endif

