[JENKINS-20356] windows-compliant GIT_SSH
work in progress, failing now :

Fetching upstream changes from git@github.com:cloudbees/test.git
using GIT_SSH to set credentials 
FATAL: Failed to fetch from git@github.com:cloudbees/test.git
hudson.plugins.git.GitException: Failed to fetch from git@github.com:cloudbees/test.git
	at hudson.plugins.git.GitSCM.fetchFrom(GitSCM.java:617)
	at hudson.plugins.git.GitSCM.retrieveChanges(GitSCM.java:841)
	at hudson.plugins.git.GitSCM.checkout(GitSCM.java:866)
	at hudson.model.AbstractProject.checkout(AbstractProject.java:1256)
	at hudson.model.AbstractBuild$AbstractBuildExecution.defaultCheckout(AbstractBuild.java:589)
	at jenkins.scm.SCMCheckoutStrategy.checkout(SCMCheckoutStrategy.java:88)
	at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:494)
	at hudson.model.Run.execute(Run.java:1502)
	at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:46)
	at hudson.model.ResourceController.execute(ResourceController.java:88)
	at hudson.model.Executor.run(Executor.java:236)
Caused by: hudson.plugins.git.GitException: Command "fetch -t git@github.com:cloudbees/test.git +refs/heads/*:refs/remotes/origin/*" returned status code 128:
stdout: Process leaked file descriptors. See http://wiki.jenkins-ci.org/display/JENKINS/Spawning+processes+from+build for more information

stderr: fatal: protocol error: bad line length character: 
C:
select: Bad file number