updating the carbon-p2-plugin version to 1.5.4-SNAPSHOT
reverting the carbon-p2-plugin version to 1.5.3
Merge pull request #91 from manoj-kumara/release-4.3.0

sucessfully commited the changes
Timestamp : Tue Nov 18 18:30:12 IST 2014
https://wso2.org/jenkins-pr-builder/job/carbon4-kernel/645/