Fix version number output in stats

The version number was previously being output as a number. In
the case of the current version (1.10) this was parsed as 1.1 by
several YAML parsers, including Ruby's, js-yaml and Perl 6's
YAMLish. In order for the version number to be parsed correctly
it needs to be a string since the trailing zeros are significant.

This change shouldn't affect any existing parsers as the ones
that got the correct number are parsing all values as strings
anyway.

Of course, since this won't be released until a later version, it
won't help. At least not until 1.20 or 2.10.

prot.c

@@ -176,7 +176,7 @@ size_t job_data_size_limit = JOB_DATA_SIZE_LIMIT_DEFAULT;
     "current-waiting: %u\n" \
     "total-connections: %u\n" \
     "pid: %ld\n" \
-    "version: %s\n" \
+    "version: \"%s\"\n" \
     "rusage-utime: %d.%06d\n" \
     "rusage-stime: %d.%06d\n" \
     "uptime: %u\n" \