Adding changes related to sed -i for mac osx

This change is mainly due to incompatibility issues occurred in stratos when user run it on a mac os x.
A work around solution is to use gsed instead of sed.
How to install gsed in mac osx:
   i. Installed homebrew(http://brew.sh/)
    $ ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
    ii. Installed gnu-sed
    $ brew install gnu-sed

changes are made in:
stratos / tools / stratos-installer /
  demo.sh, ec2.sh,openstack.sh, setup.sh and vcloud.sh
stratos / tools / stratos-installer / scripts /
  add_entry_zone_file.sh and remove_entry_zone_file.sh 

Other than that this change also include syntax errors which can be found in setup.sh line 605:
-chown -R $host_user.$host_user $log_path
+chown -R $host_user:$host_user $log_path
This code change is done by @Prasanna Dangalla

JIRA - https://issues.apache.org/jira/browse/STRATOS-816