Upgrade devel/protobuf-c to 1.1.1

[truckman]

Summary

[ Robert Edmonds ]
* Release 1.1.1.
 
* Use protobuf 2.6.1 in the Travis-CI environment.
 
[ Ilya Lipnitskiy ]
* Munge C block comment delimiters in protobuf comments, preventing syntax
  errors in generated header files (Issue #180, #185).
 
* Add static qualifier to ProtobufCEnumValue and ProtobufCEnumValueIndex
  variables in generated output.
 
[ Oleg Efimov ]
* Fix -Wpointer-sign compiler diagnostics in the test suite.
 
* Check for NULL pointers in protobuf_c_message_free_unpacked()
  (Issue #177).
 
* Exclude protoc-c and downloaded protobuf sources from Coveralls report.
 
[ Andrey Myznikov ]
* Fix incorrect 'short_name' field values in ProtobufCServiceDescriptor
  variables in generated output.

Test Plan

Build on FreeBSD 8.4, 9.3, 10.1, and 11.0-CURRENT, both amd64 and i386