Problem
I checked there is no rmr2 package included.
Solution
First download rmr2_3.0.0.tar.gz from gitHub and then from your r terminal install.packages("/home/satya/Downloads/rmr2_3.0.0.tar.gz") at the place of satya you can write your user name.https://github.com/RevolutionAnalytics/RHadoop/wiki/rmr as rmr2 installation is slightly different.
Also you are advised to run update.packages before install.packages to ensure that any already installed dependencies have their latest versions. Please refer to