make sure to set p9unix

src/lib9/_p9dialparse.c

diff --git a/src/lib9/_p9dialparse.c b/src/lib9/_p9dialparse.c
index c464e9f..d3dc1ee 100644
--- a/src/lib9/_p9dialparse.c
+++ b/src/lib9/_p9dialparse.c
@@ -85,6 +85,7 @@
 	if(strncmp(addr, "/net/", 5) == 0)
 		addr += 5;
 
+	*punix = nil;
 	net = addr;
 	if((host = strchr(net, '!')) == nil){
 		werrstr("malformed address");