apply.pl now does not die() when the target directory already

exists, it will come up with a unique name.  usage_apply() in
aux.pm updated to reflect this.

misc-scripts/binary_delta/apply.pl

@@ -52,9 +52,8 @@ my $delta_dir = sprintf "%s/%s_%s_delta_%s", $dst_prefix, $db, $v1, $v2;
 die $! if (! -d $v1_dir);
 die $! if (! -d $delta_dir);
 
-if (-d $v2_dir) {
-    printf STDERR "Whoa, the directory '%s' already exists\n", $v2_dir;
-    die $!;
+while (-d $v2_dir) {
+    $v2_dir = sprintf "%s.%04d", $v2_dir, int(rand(10000));
 }
 
 printf STDERR "Creating the directory '%s'\n", $v2_dir;

misc-scripts/binary_delta/aux.pm

@@ -86,7 +86,8 @@ The options may be any of these:
         Default: "$opts->{'s'}"
 -d path Path to the directory holding the old version of the
         database, and where the new version of the database
-        should be created.
+        should be created.  The new database directory will be
+        given a unique name.
         Default: "$opts->{'d'}"
 
 EOT