Now that vshCommandRun() checks for the connection automaticaly, remove
all of the redundant checks in the code.
vshConnectionUsability() no longer needs to be exported and this patch
marks it static.
Another worthwhile split, needed one more public function.
* tools/virsh-nodedev.h: New file.
* tools/Makefile.am (virsh_SOURCES): Build it.
* tools/virsh-nodedev.c: Use new header.
* tools/virsh.c: Likewise.
(vshTreePrint): Export.
* tools/virsh.h (vshTreePrint): Declare.
Commands in node device group moved from virsh.c to virsh-nodedev.c,
* virsh.c: Remove commands in node device group.
* virsh-nodedev.c: New file, filled with commands in node device group
* po/POTFILES.in: Add virsh-nodedev.c
* cfg.mk: Skip to check config.h including for virsh-nodedev.c