tests/microbenchs: fix equality test for sh

tests/microbenchs/microbench.sh

@@ -1,7 +1,7 @@
 # StarPU --- Runtime system for heterogeneous multicore architectures.
 #
 # Copyright (C) 2016  Université de Bordeaux
-# Copyright (C) 2016  CNRS
+# Copyright (C) 2016, 2017  CNRS
 #
 # StarPU is free software; you can redistribute it and/or modify
 # it under the terms of the GNU Lesser General Public License as published by
@@ -40,13 +40,13 @@ test_scheds()
 	    	STARPU_SCHED=$sched $(dirname $0)/$TEST
 		ret=$?
 	    	set -e
-		if test $ret == 0
+		if test $ret = 0
 		then
 		    	echo "SUCCESS: STARPU_SCHED=$sched ./microbenchs/$TEST"
 			pass="$pass $sched"
 			continue
 		fi
-		if test $ret == 77
+		if test $ret = 77
 		then
 		    	echo "SKIP: STARPU_SCHED=$sched ./microbenchs/$TEST"
 			skip="$skip $sched"

tests/microbenchs/tasks_size_overhead_sched.sh

@@ -21,7 +21,7 @@ ROOT=${ROOT%_sched}
 unset STARPU_SSILENT
 $ROOT "$@" > tasks_size_overhead.output
 ret=$?
-if test "$ret" == "0"
+if test "$ret" = "0"
 then
     # if the program was successfull try to run gnuplot
     DIR=