DAG: Remove the strrchr() call from pcap_create(). [skip ci]

The original intention was likely to skip the optional "/dev/" in
"/dev/dag0" to support a larger subset of what dag_parse_name()
implements.  It does not work this way because the pointer strrchr()
returns points to the last '/' and the test for the first three
characters being "dag" in "/dag0" is always negative:

$ tcpdump -ni /dev/dag0
tcpdump: This version of libpcap only supports DAG cards

Remove the broken code for now to simplify the module refactoring.  If
there is a good reason to support DAG device aliases in addition to the
nominal names in libpcap, it will not be difficult to add that.

Author: infrastation

pcap-dag.c

@@ -902,9 +902,7 @@ pcap_t *dag_create(const char *device, char *ebuf, int *is_ours)
 	long stream = 0;
 
 	/* Does this look like a DAG device? */
-	cp = strrchr(device, '/');
-	if (cp == NULL)
-		cp = device;
+	cp = device;
 	/* Does it begin with "dag"? */
 	if (strncmp(cp, "dag", 3) != 0) {
 		/* Nope, doesn't begin with "dag" */