Fix tests when executed by Jenkins slaves

The Puppet tests fail on Jenkins because bundler tries to install the
Ruby gems to the default GEM_HOME which is protected. This change sets
the GEM_HOME variable to a local directory.

Change-Id: I65d65358ca0c0fb9d01ed73bb156334fa5fa6edc

.gitignore

@@ -0,0 +1 @@
+.bundled_gems/

tox.ini

@@ -5,15 +5,25 @@ skipsdist = True
 [testenv:lma_logging_analytics]
 deps =
 changedir = {toxinidir}/deployment_scripts/puppet/modules/{envname}
-whitelist_externals = bundle
+whitelist_externals =
+    bundle
+    mkdir
+setenv =
+    GEM_HOME={toxinidir}/.bundled_gems
 commands =
+    mkdir -p {toxinidir}/.bundled_gems
     bundle install
     bundle exec rake test
 
 [testenv:disk_management]
 deps =
 changedir = {toxinidir}/deployment_scripts/puppet/modules/{envname}
-whitelist_externals = bundle
+whitelist_externals =
+    bundle
+    mkdir
+setenv =
+    GEM_HOME={toxinidir}/.bundled_gems
 commands =
+    mkdir -p {toxinidir}/.bundled_gems
     bundle install
     bundle exec rake test