Merge branch 'ruby18-errors' into 'master'

Ruby18 errors

Fixes some errors on CentOS 6.

```
$ byteback-prune
/usr/bin/byteback-receive:120: undefined method `+' for nil:NilClass (NoMethodError)
	from /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `inject'
	from /usr/bin/byteback-receive:119:in `each'
	from /usr/bin/byteback-receive:119:in `inject'
	from /usr/bin/byteback-receive:119


# byteback-backup
/usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require': /usr/share/byteback/byteback/backup_directory.rb:154: syntax error, unexpected '.', expecting kEND (SyntaxError)
          .compact
           ^
/usr/share/byteback/byteback/backup_directory.rb:194: syntax error, unexpected '.', expecting kEND
        .compact
         ^
	from /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
	from /usr/share/byteback/byteback.rb:3
	from /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
	from /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
	from /usr/bin/byteback-receive:11
```


See merge request !1

1 files changed, 1 insertions, 1 deletions

diff --git a/bin/byteback-receive b/bin/byteback-receive
index 0d7d025..1326bba 100755
--- a/bin/byteback-receive
+++ b/bin/byteback-receive
@@ -116,7 +116,7 @@ end
 # Make sure we don't get crazy option combinations.
 #
 n_modes = opts.keys.inject(0) do |s,m|
-    s += 1 if  [:ping, :complete, :list].include?(m)
+    [:ping, :complete, :list].include?(m) ? s += 1 : s
 end
 
 error('Please only choose one mode') unless n_modes == 1