remove some bashisms

[[Imported from SVN: r4716]]

bin/dunecontrol

@@ -143,16 +143,16 @@ run_default_autogen () {
 run_default_configure () {
   PARAMS="$CMD_PARAMS"
   if test -x configure; then
-    if test "x$HAVE_dune_common" == "xyes"; then
+    if test "x$HAVE_dune_common" = "xyes"; then
       PARAMS="$PARAMS \"--with-dune-common=$PATH_dune_common\""
     fi
-    if test "x$HAVE_dune_grid" == "xyes"; then
+    if test "x$HAVE_dune_grid" = "xyes"; then
       PARAMS="$PARAMS \"--with-dune-grid=$PATH_dune_grid\""
     fi
-    if test "x$HAVE_dune_istl" == "xyes"; then
+    if test "x$HAVE_dune_istl" = "xyes"; then
       PARAMS="$PARAMS \"--with-dune-istl=$PATH_dune_istl\""
     fi
-    if test "x$HAVE_dune_disc" == "xyes"; then
+    if test "x$HAVE_dune_disc" = "xyes"; then
       PARAMS="$PARAMS \"--with-dune-disc=$PATH_dune_disc\""
     fi
     echo ./configure "$PARAMS"
@@ -218,7 +218,7 @@ usage () {
     echo
 }
 
-if test "x$1" == "x"; then
+if test "x$1" = "x"; then
   usage
   exit 1
 fi
@@ -241,7 +241,7 @@ while test $# -gt 0; do
     # switch
     case "$option" in
     --opts=*)
-      if test "x$arg" == "x"; then
+      if test "x$arg" = "x"; then
         usage
         echo "ERROR: Parameter for --opts is missing"
         echo
@@ -264,7 +264,7 @@ while test $# -gt 0; do
       break
     ;;
     --module=*)
-      if test "x$arg" == "x"; then
+      if test "x$arg" = "x"; then
         usage
         echo "ERROR: Parameter for --module is missing"
         echo
@@ -273,7 +273,7 @@ while test $# -gt 0; do
       fix_and_assign MODULE "$arg"
     ;;
     --only=*)
-      if test "x$arg" == "x"; then
+      if test "x$arg" = "x"; then
         usage
         echo "ERROR: Parameter for --only is missing"
         echo