libuuid, uuidd: Avoid infinite loop while reading from the socket fd

libuuid, uuidd: Avoid infinite loop while reading from the socket fd

If for some reason the uuidd daemon or the process calling uuidd
exited unexpectely, the read_all() function would end up looping
forever, either in uuidd or in libuuid.  Fix this terminating the loop
if no data can be read after five tries to read from the file
descriptor.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>