build-ceph-rpm.sh: fix the bogus date in changelog

build-ceph-rpm.sh: fix the bogus date in changelog

rpmbuild complains at seeing the bogus date:
```
warning: bogus date in %changelog: Tue Mar 10 2013 Gary Lowell - 1-0
warning: bogus date in %changelog: Tue Aug 27 2012 Gary Lowell - 1-0
```
so update the weekday to applease it.

also follows
https://docs.fedoraproject.org/en-US/Fedora_Draft_Documentation/0.1/html/Packagers_Guide/sect-Packagers_Guide-Creating_a_Basic_Spec_File.html
to remove the hyphen before version number.

Signed-off-by: Kefu Chai <tchaikov@gmail.com>