On "Bundle exec rake assets:precompile", we received an error like,"Rake aborted" and No clue about the problem that created this issue.But on the line which this error was thrown had its reference to excon gem which was running smoothly few days ago.
Basically the issue was with recent bundle update, which updated the excon gem from 0.9.5 to 0.9.6 in Gemfile.lock which maintains all dependencies.
So inclusion of excon gem with version number 0.9.5 fixed the issue.