ceph.spec.in: fix 'Requires:' to get sgdisk into the system

Fix package Requirements to get sgdisk. On RHEL/CentOS/Fedora the
package is gdisk. On SUSE/openSUSE < 12.2 it's scsirastools on
openSUSE >= 12.2 it's in gptfdisk.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
ceph.spec.in: add on non-RHEL sharutils to 'BuildRequires:'

Add sharutils to 'BuildRequires:', needed for configure.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
ceph.spec.in: merge fdupes support from SUSE packages

Use fdupes to avoid duplicated files as done in the SUSE
packages. Since it doesn't work as expected on Fedora/RHEL
do this only on SUSE based distros.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
Merge pull request #85 from dalgaaf/wip-da-spec-1

Fix package requirements to get sgdisk and merge some changes back from SUSE spec file.

Reviewed-by: Gary Lowell <gary.lowell@inktank.com>