tests/nfs_filesystem: comment out failing mount

For reasons unclear, we attempt to mount twice, the 2nd time yields EBUSY,
and then the following test fails. Comment out the 2nd mount, which also
resolves the failure.

This bug is tracked in
#92

Before:
Run NFS context specific tests
nfs_filesystem/test .. 2/56 creat(2) Failed: Permission denied

#   Failed test at nfs_filesystem/test line 118.
nfs_filesystem/test .. 30/56 creat(2) Failed: Permission denied

#   Failed test at nfs_filesystem/test line 118.
nfs_filesystem/test .. 53/56 # Looks like you failed 2 tests of 56.
nfs_filesystem/test .. Dubious, test returned 2 (wstat 512, 0x200)
Failed 2/56 subtests

Test Summary Report
-------------------
nfs_filesystem/test (Wstat: 512 (exited 2) Tests: 56 Failed: 2)
  Failed tests:  7, 35
  Non-zero exit status: 2
Files=1, Tests=56, 12 wallclock secs ( 0.02 usr  0.00 sys +  0.15 cusr  0.25 csys =  0.42 CPU)
Result: FAIL
Failed 1/1 test programs. 2/56 subtests failed.
Error on line: 104 - Closing down NFS
umount: /mnt/selinux-testsuite: not mounted.
NFS Closed down

After:
No errors from this test script.

Signed-off-by: Stephen Smalley <[email protected]>
Signed-off-by: Ondrej Mosnacek <[email protected]>

tests/nfs_filesystem/test

@@ -38,7 +38,11 @@ BEGIN {
         $v = " ";
     }
 
-    plan tests => 56;
+    # A test (called twice) is commented out because it does not work
+    # for any known kernel.
+    # See https://github.com/SELinuxProject/selinux-testsuite/issues/92
+    #plan tests => 56;
+    plan tests => 54;
 }
 
 # Set for testing mount(2) on first run
@@ -100,16 +104,19 @@ while ( $i < 2 ) {
     );
     ok( $result eq 0, $test_msg );
 
-    # First mount(2) ok, second currently fails with EBUSY
-    $result = system(
-"runcon -t test_filesystem_t $mount_cmd $v -s $dev -t $target -f $fs_type -o $mount_opts 2>&1"
-    );
-    if ( $i eq 0 and $result >> 8 eq 16 ) {
-        ok( 1, "$test_msg - returned EBUSY, possible bug/feature" );
-    }
-    else {
-        ok( $result eq 0 );
-    }
+# The following test is commented out because it does not work
+# for any known kernel.
+# See https://github.com/SELinuxProject/selinux-testsuite/issues/92
+# First mount(2) ok, second currently fails with EBUSY
+#    $result = system(
+# "runcon -t test_filesystem_t $mount_cmd $v -s $dev -t $target -f $fs_type -o $mount_opts 2>&1"
+#    );
+#    if ( $i eq 0 and $result >> 8 eq 16 ) {
+#        ok( 1, "$test_msg - returned EBUSY, possible bug/feature" );
+#    }
+#    else {
+#        ok( $result eq 0 );
+#    }
 
     # Create file and change context via type_transition rule, check ok:
     $result = system(