Hello, Sergey.

What version of cloud-init is usually used in centos? From EPEL?
Here  http://dl.fedoraproject.org/pub/epel/6/x86_64/repoview/cloud-init.html
I can see  only this version: cloud-init-0.7.4-2.el6.noarch

But in epel7 repo
http://dl.fedoraproject.org/pub/epel/7/x86_64/repoview/cloud-init.html
cloud-init-0.7.5-6.el7.x86_64 is available

On fuel 6.0 changelog 
rpm -qp --changelog /var/www/nailgun/2014.2-6.0/centos/x86_64/Packages/cloud-init-0.7.4-2.mira1.noarch.rpm
and changelog of that package downloaded from epel are the same
rpm -qp --changelog cloud-init-0.7.4-2.el6.noarch

Even though size of packages are  different:
[root@fuel mira]# ll cloud-init-0.7.4-2.mira1.noarch.rpm 
-rwxr-xr-x 1 root root 498732 Jan  4 02:02 cloud-init-0.7.4-2.mira1.noarch.rpm
[root@fuel epel]# ll cloud-init-0.7.4-2.el6.noarch.rpm 
-rw-r--r-- 1 root root 498952 Feb  9 02:37 cloud-init-0.7.4-2.el6.noarch.rpm

I extracted packages with
rpm2cpio cloud-init-0.7.4-2.mira1.noarch.rpm | cpio -idmv
rpm2cpio cloud-init-0.7.4-2.el6.noarch.rpm  | cpio -idmv

And found that only difference is  cc_keys_to_console.pyc and cc_keys_to_console.pyo  files. Even though source  code cc_keys_to_console.py is the same. All other files have same md5sum too.

[root@fuel config_mira]# md5sum cc_keys_to_console.py 
1eb40f754817fa1e468d4af72b368d55  cc_keys_to_console.py

[root@fuel config_epel]# md5sum cc_keys_to_console.py 
1eb40f754817fa1e468d4af72b368d55  cc_keys_to_console.py

[root@fuel config_mira]# md5sum cc_keys_to_console.pyc 
2f3d3e8f4911d588e8a95484aa12f671  cc_keys_to_console.pyc

[root@fuel config_epel]# md5sum cc_keys_to_console.pyc 
77a5a33a70d762d44a9c934056fde1ca  cc_keys_to_console.pyc

[root@fuel config_mira]# md5sum cc_keys_to_console.pyo 
2f3d3e8f4911d588e8a95484aa12f671  cc_keys_to_console.pyo

[root@fuel config_epel]# md5sum cc_keys_to_console.pyo 
77a5a33a70d762d44a9c934056fde1ca  cc_keys_to_console.pyo
  
So, should we file a bug in centos|rhel bugtracker?
What our customers should do, before it is fixed in upstream? Probably, you can share you rebuilded version of package?

UPD:
I found cloud-init-0.7.5-10.el6.centos.2.src.rpm in centos extras repo for centos 6.6 
http://vault.centos.org/6.6/extras/Source/SPackages/
And spec there contains packages, that you mentioned 
Patch0001: 0001-update-paths-for-rhel.patch
Patch0002: 0002-fix-rsyslog-programname-match.patch
Patch0003: 0003-Stopped-calling-udevadm-settle-with-quiet-since-syst.patch
Patch0004: 0004-fix-typo-in-settings.py-preventing-metadata-being-fe.patch

Patch1001: cloud-init-centos-opennebula.patch
Patch1002: cloud-init-centos-hostnamefix.patch
Patch1003: cloud-init-centos-opennebula-requiretty.patch
Patch1004: cloud-init-centos-cloudstack-urlhandling.patch


But source rpmcloud-init-0.7.4-2.el6.src.rpm   from here  https://dl.fedoraproject.org/pub/epel/6/SRPMS/
doesn't contain patches, that you mentioned.
Version:        0.7.4
Release:        2%{?dist}
Summary:        Cloud instance init scripts

Group:          System Environment/Base
License:        GPLv3
URL:            http://launchpad.net/cloud-init
Source0:        https://launchpad.net/cloud-init/trunk/%{version}/+download/cloud-init-%{version}.tar.gz
Source1:        cloud-init-rhel.cfg
Source2:        cloud-init-README.fedora
Patch0:         cloud-init-0.7.2-fedora.patch