LU-2274 tests: use ext3 as baseline for POSIX test on SLES

LU-2274 tests: use ext3 as baseline for POSIX test on SLES

Since SLES distro does not support read-write access to an ext4
file system by default, this patch changes the baseline filesystem
to ext3 for POSIX testing on SLES distro.

The patch also removes the package installation codes from the
test script, which can detect and prompt which mandatory package
is not installed.

Test-Parameters: envdefinitions=SLOW=yes clientdistro=sl11 testlist=posix
Signed-off-by: Yu Jian <yujian@whamcloud.com>
Change-Id: Iac901bb62afe0a944e8211e73bacb061e9a3aac1
Reviewed-on: http://review.whamcloud.com/4524
Tested-by: Hudson
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Minh Diep <minh.diep@intel.com>