check_yum --all-updates fails with package info on multiple lines

[ronaldoussoren]

yum check-output splits output about a package over two lines with the package name is long, like so:

java-1.7.0-openjdk-devel.x86_64
                               1:1.7.0.99-2.6.5.0.el6_7 rhel-6-server-rpms    

This confuses the code in get_all_updates().

A crude hack to fix this is to post-process the return value of self.run(cmd): append any line that starts with whitespace to the preceding line.