libfuse : convert to autotools infrastructure & bump to 2.8.4

Changes by Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

 * Installation to target is the default
 * Remove incorrect libfuse-dirclean target
 * Remove INSTALL_STAGING_CMDS, since its implementation was the default behaviour
 * No need to strip, done globally
 * No need to create main directories in $(TARGET_DIR)

Signed-off-by: cmchao <cmchao@gmail.com>