hush: do not use ps -o in leak_argv1; do not hardcode path in negate

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

shell/hush_test/hush-parsing/negate.right

@@ -33,3 +33,4 @@ c 1
 1
 1
 1
+Done

shell/hush_test/hush-parsing/negate.tests

@@ -7,10 +7,13 @@ if ! false; then false; echo $?; fi
 echo $?
 if ! false; then ! false; echo $?; fi
 echo $?
+PRINTF=`which printf`
 for a in ! a b c; do echo $a; done
 for a in ! a b c; do ! printf "$a "; echo $?; done
-for a in ! a b c; do ! /usr/bin/printf "$a "; echo $?; done
+test x"$PRINTF" = x"" && exit 1
+for a in ! a b c; do ! "$PRINTF" "$a "; echo $?; done
 for a in ! a b c; do ! printf "$a " | false; echo $?; done
 for a in ! a b c; do ! printf "$a " | true; echo $?; done
 for a in ! a b c; do ! { printf "$a " | false; }; echo $?; done
 for a in ! a b c; do ! { printf "$a " | true; }; echo $?; done
+echo Done