ACCUMULO-1835 Add -f, -x and -r docs to test/system/auto/README

Signed-off-by: Eric Newton <eric.newton@gmail.com>
ACCUMULO-1835 merge to 1.5
ACCUMULO-1832 fixed build issue
Revert "ACCUMULO-1761 use file size information from !METADATA instead of asking the namenode, avoids using ServerConstants.getTablesDirs()"

This reverts commit dcb559165b587eca9e5bf0b64df8031c748d3f37.
ACCUMULO-1761 learn table directories from the !METADATA table scan
ACCUMULO-1857 Clean up the README to be more informative about what
users must do instead of guessing at what their distribution might do.
Merge branch '1.5.1-SNAPSHOT' into 1.6.0-SNAPSHOT

Conflicts:
	test/system/auto/README
Merge branch '1.6.0-SNAPSHOT'