After updating to Jenkins V1.590, All my connections from master (debian 7 64 bit) to slaves (Windows/cygwin, linux and Mac OS X) don't work anymore.
Now, the situation is the following one:

• I can't use "Launch slave via execution of command on the Master" for 2 reasons:
  1 - my ssh command is truncated:
  ssh user@slave "java -jar slave.jar -jnlpUrl http://jenkins-master/computer/win7-32/slave-agent.jnlp -secret _T_H_E___S_E_C_R_E_T_"
  becomes:
  ssh user@slave java -jar slave.jar
  2 - node log page remains empty
• I can't use "Launch slave agents on Unix machines via ssh" and node log page is empty. Then it does not let me a way to understand what is the root problem.

I tried to revert to Jenkins LTS V1.580.1 but it does not change anything.

As a test, I have set upan other jenkins master installation with LTS 1.580.1. from scratch and in another hardware server. Connections to the same previous slaves are working like a charm with this master.