contrib: simple script to check for stale show_help messages / usage

This script can be run from any sub-tree in the OMPI code base.  It
does several things:

* Find all help-*txt files and index all the topics found in the
  sub-tree.
* Find all C/C++ source files (.c, .cc, .h) in the sub-tree, and look
  for various flavors of the opal_show_help() function (e.g.,
  including orte_show_help()) and search for hard-coded filenames and
  topics.
* Also look for special tokens (in comments) in the source code for
  help topics that are not necessarily hard-coded (e.g., topics that
  are snprintf'ed).
* For each filename/topic found, output a warning if a) the file does
  not exist, or b) that the topic does not exist in that file.
* Output a warning for any topic that is not referenced in the source
  code (i.e., orphaned/now-unused help messages).
* Output a warning for any help file that appears to be empty.
* Output a warning for any help file that appears to be unused (i.e.,
  no topics in the help file are referenced in code).
opal wrappers: Remove unused help message; add missing help message
opal cr: Remove some unused help messages
db base: Remove now-unused helpfile.

The only help message in this file wasn't being used, so remove the
whole file.
db sqlite: Add missing help message
memory linux: show_help.h is not needed in this file
memory linux: This is a level 3 MCA param

I.e., make it just like all the other MCA params in this component.

cmr=v1.8.1:reviewer=hjelmn
memory linux: Remove unused help message.

This type of help message is now handled by the MCA var system itself
(via the MCA_BASE_VAR_FLAG_ENVIRONMENT_ONLY flag at var_register
time).
sec base: show_help isn't used in the sec base
hwloc base: Remove unused help messages.

These type of help messages are now displayed by the MCA var system
itself (via enumerated values).
hwloc/rmaps base: Add missing help message.

Also, add missing ORTE_ERROR_LOG in the other case where this error
message is used (i.e., ORTE_ERROR_LOG was used in the one place, so
let's also use it in the other place).
btl usnic: Add some SHOW_HELP: tokens and remove 2 unused help messages
crs: Remove empty help text file
crs self: Remove unused help message.

Also:

* fix formatting error at top (make the emacs format line begin
  with a comment character)
* Remove blank lines between topics and replace them with empty
  comment lines (so that the help messages are not displayed with a
  trailing blank line)
opal: Remove unused help message.

Help messages about deprecated variables are now provided by the MCA
var system.
mca base: Remove unused help message.
mca base: Remove unused help file.

The contents of this file were superceded by mca-help-var.txt.
Indeed, this file was already removed from Makefile.am; it looks like
it was accidentally left in SVN.
compress/crs: Remove empty help files.

Aside from comments, these help files are empty -- so just remove
them.  Also remove a few inclusions of show_help.h, since it isn't
used in those source files.