Properly mirror child exit status in ksu

ksu attempts to exit with the same status as its child process, but
does not do so correctly.  Use WEXITSTATUS() to extract the exit code.
Reported by Todd Lubin.

ticket: 8618

src/clients/ksu/main.c

@@ -780,7 +780,7 @@ main(int argc, char ** argv)
                 com_err(prog_name, errno, _("while calling waitpid"));
             }
             sweep_up(ksu_context, cc_target);
-            exit (statusp);
+            exit (WIFEXITED(statusp) ? WEXITSTATUS(statusp) : 1);
         case -1:
             com_err(prog_name, errno, _("while trying to fork."));
             sweep_up(ksu_context, cc_target);

src/clients/ksu/t_ksu.py

@@ -244,7 +244,7 @@ def remove_authz_file(fname):
 realm.run([ksu, '.', '-e', klist],
           expected_msg='Default principal: alice@KRBTEST.COM')
 be_root()
-realm.run([ksu, 'ksutest', '-e', klist],
+realm.run([ksu, 'ksutest', '-e', klist], expected_code=1,
           expected_msg='No credentials cache found')
 be_caller()
 realm.kinit('ksutest', 'pwksutest')
@@ -253,7 +253,8 @@ def remove_authz_file(fname):
           expected_msg='Default principal: ksutest@KRBTEST.COM')
 be_caller()
 realm.run([kdestroy])
-realm.run([ksu, '.', '-e', klist], expected_msg='No credentials cache found')
+realm.run([ksu, '.', '-e', klist], expected_code=1,
+          expected_msg='No credentials cache found')
 
 mark('authentication without authorization')
 realm.run([ksu, '.', '-n', 'ksutest', '-e', klist], input='pwksutest\n',
@@ -266,6 +267,7 @@ def remove_authz_file(fname):
 realm.run([ksu, '.', '-z', '-e', klist],
           expected_msg='Default principal: ' + caller_username)
 
-realm.run([ksu, '.', '-Z', '-e', klist])
+realm.run([ksu, '.', '-Z', '-e', klist], expected_code=1,
+          expected_msg='No credentials cache found')
 
 success('ksu tests')