test/fflush.sh: Remove hardcoded gawk path.

Signed-off-by: Anders Roxell <anders.roxell@enea.com>
Upstream-Status: Pending
---
--- a/test/fflush.sh	2012-05-03 20:13:57.000000000 +0200
+++ b/test/fflush.sh	2013-04-08 16:28:00.170796200 +0200
@@ -1,16 +1,17 @@
 #! /bin/sh
-../gawk 'BEGIN{print "1st";fflush("/dev/stdout");print "2nd"|"cat"}'
+AWK=${AWK-../gawk}
+$AWK 'BEGIN{print "1st";fflush("/dev/stdout");print "2nd"|"cat"}'
 
-../gawk 'BEGIN{print "1st";fflush("/dev/stdout");print "2nd"|"cat"}'|cat
+$AWK 'BEGIN{print "1st";fflush("/dev/stdout");print "2nd"|"cat"}'|cat
 
-../gawk 'BEGIN{print "1st";fflush("/dev/stdout");close("/dev/stdout");print "2nd"|"cat"}'|cat
+$AWK 'BEGIN{print "1st";fflush("/dev/stdout");close("/dev/stdout");print "2nd"|"cat"}'|cat
 
-../gawk 'BEGIN{print "1st";fflush("/dev/stdout");print "2nd"|"cat";close("cat")}'|cat
+$AWK 'BEGIN{print "1st";fflush("/dev/stdout");print "2nd"|"cat";close("cat")}'|cat
 
-../gawk 'BEGIN{print "1st";fflush("/dev/stdout");print "2nd"|"cat";close("cat")}'|cat
+$AWK 'BEGIN{print "1st";fflush("/dev/stdout");print "2nd"|"cat";close("cat")}'|cat
 
-../gawk 'BEGIN{print "1st";fflush("/dev/stdout");print "2nd"|"cat";close("cat")}'|cat
+$AWK 'BEGIN{print "1st";fflush("/dev/stdout");print "2nd"|"cat";close("cat")}'|cat
 
-../gawk 'BEGIN{print "1st";fflush("/dev/stdout");print "2nd"|"sort"}'|cat
+$AWK 'BEGIN{print "1st";fflush("/dev/stdout");print "2nd"|"sort"}'|cat
 
-../gawk 'BEGIN{print "1st";fflush("/dev/stdout");print "2nd"|"sort";close("sort")}'|cat
+$AWK 'BEGIN{print "1st";fflush("/dev/stdout");print "2nd"|"sort";close("sort")}'|cat