Remove extra const qualifiers.

Some function declared parameters like this:
	int f(const char * const s)
Where appropriate, I changed to
	int f(const char *s)

The second const is a qualifier on the pointer itself; i.e., the value
of s may not be changed (may not be made to point to anything else)
within the function. This is probably not what was intended. The first
const is what prevents modifying things referenced through s.

TargetGroup.h

@@ -114,7 +114,7 @@ class TargetGroup {
     such as 192.168.0.0/16 , 10.1.0-5.1-254 , or
     fe80::202:e3ff:fe14:1102 .  The af parameter is AF_INET or
     AF_INET6 Returns 0 for success */
-  int parse_expr(const char * const target_expr, int af);
+  int parse_expr(const char *target_expr, int af);
   /* Grab the next host from this expression (if any).  Returns 0 and
      fills in ss if successful.  ss must point to a pre-allocated
      sockaddr_storage structure */