clang unconditionalized variable complaint
sort the switch options, fix the switch formatting.
Tables aren't "wt", they're "wt.wt", fix things up so we corrupt them
too, and test salvage.
Minor shuffling to turn on more clang warnings:

- a few more uninitialized variables
- make variables local to a single file static
- replace use of WT_UNUSED_RET with error checking of the call (the
	macro was using a GCC extension clang doesn't like)

With these changes, clang is mostly silent using the following options:

	-Weverything
	-Wno-cast-align
	-Wno-conversion
	-Wno-covered-switch-default
	-Wno-documentation-unknown-command
	-Wno-format-nonliteral
	-Wno-language-extension-token
	-Wno-missing-noreturn
	-Wno-packed
	-Wno-padded
	-Wno-switch-enum
	-Wno-zero-length-array

Also, minor KNF whitespace cleanups.