[FIXED JENKINS-12572] Add environment variable pointing to temporary logcat file during a build.
[FIXED JENKINS-16720] Ensure SDK version check is done on the right node.

Previously, when automatically installing the SDK, we were instantiating
an SDK object on the master, meaning that we were inspecting the tools
version file on the master, rather than on the node in question.

Also removed the empty catch block which was masking this problem.