use commit hash for net-imap

to catch up new sharable proc semantics.

Author: ko1

gems/bundled_gems

@@ -13,7 +13,7 @@ test-unit           3.7.0   https://github.com/test-unit/test-unit
 rexml               3.4.2   https://github.com/ruby/rexml
 rss                 0.3.1   https://github.com/ruby/rss
 net-ftp             0.3.8   https://github.com/ruby/net-ftp
-net-imap            0.5.10  https://github.com/ruby/net-imap
+net-imap            0.5.10  https://github.com/ruby/net-imap 71c0288b9a8f78a7125a4ce2980ab421acdf5836
 net-pop             0.1.2   https://github.com/ruby/net-pop
 net-smtp            0.5.1   https://github.com/ruby/net-smtp
 matrix              0.4.3   https://github.com/ruby/matrix