lookup NDBFILE before defaulting to /lib/ndb/local.  not sure how
this one was missed.

Reference: /n/atom/patch/applied/ndbopenenv
Date: Sun Jan 10 18:23:53 CET 2016
Signed-off-by: quanstro@quanstro.net

--- /sys/src/libndb/ndbopen.c	Sun Jan 10 18:22:48 2016
+++ /sys/src/libndb/ndbopen.c	Sun Jan 10 18:22:50 2016
@@ -22,7 +22,7 @@
 	Ndbs s;
 	Ndbtuple *t, *nt;
 
-	if(file == 0)
+	if(file == nil && (file = getenv("NDBFILE")) == nil)
 		file = deffile;
 	db = doopen(file);
 	if(db == 0)