package/jailhouse: fix misc details in Config.in

This commit fixes a number of small minor details in the jailhouse
Config.in file:

 - The Config.in comment is in the middle of the main
   BR2_PACKAGE_JAILHOUSE option and its sub-options, causing the
   sub-options to not be indented properly in menuconfig

 - jailhouse was capitalized as Jailhouse, while all Buildroot
   packages in menuconfig use small letters, so use "jailhouse"
   everywhere

 - no need to repeat "jailhouse" in the prompt of the sub-option for
   helper scripts, since it is not properly indented under the main
   jailhouse option. Ditto in the comment when python is disabled.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
[yann.morin.1998@free.fr:
  - further drop 'jailhouse' from the helper scripts comment when
    python is not enabled
]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>