helper/command: fix memory leak on malloc() fail

helper/command: fix memory leak on malloc() fail

If malloc() fails, the just allocated Jim_Obj will leaks.

Move Jim_IncrRefCount() before the malloc() and deallocate the Jim
object with Jim_DecrRefCount() on malloc() fail.

While there, add the 'out of memory' log and fix the CamelCase
name of the symbol tclOutput.

Change-Id: Ic733db229d5aa5d477d758ea9cb88cd81d7542cd
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/6188
Tested-by: jenkins
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>