Fix dreport os-release script point to a symbolic link

The os-release file in the dump points to a symbolic link
rather than the actual release details.

As "cp -r" command is used to copy the contents of a symbolic
link file, it copies the link rather than the actual file.

Modified to use cp command to copy the contents of the file

Tested:
before fix
root@witherspoon:/tmp# mkdir test1
root@witherspoon:/tmp# cp -r /etc/os-release test1/
root@witherspoon:/tmp# ls -la test1/
drwxr-xr-x    2 root     root            60 Jun  6 12:27 .
drwxrwxrwt   13 root     root           320 Jun  6 12:26 ..
lrwxrwxrwx    1 root     root            21 Jun  6 12:27 os-release -> ../usr/lib/os-release

after fix
root@witherspoon:/tmp# mkdir test2
root@witherspoon:/tmp# cp /etc/os-release test2/
root@witherspoon:/tmp# ls -la test2/
-rw-r--r--    1 root     root           295 Jun  6 12:27 os-release

Change-Id: I6980ffa40b925fb02be0bf53704d17ebc7995af0
Signed-off-by: Marri Devender Rao <devenrao@in.ibm.com>