Adjust DEPENDS to reflect current reality and make it compatible with
Python 3 too.

Bump PKGREVISION

Index: Makefile
===================================================================
RCS file: /cvsroot/pkgsrc/devel/py-protobuf/Makefile,v
retrieving revision 1.10
diff -u -p -r1.10 Makefile
--- Makefile	1 Jan 2017 14:43:34 -0000	1.10
+++ Makefile	12 May 2017 14:48:51 -0000
@@ -3,6 +3,7 @@
 .include "../../devel/protobuf/Makefile.common"
 
 DISTNAME=	protobuf-python-${PROTOBUFVER}
+PKGREVISION=	1
 PKGNAME=	${PYPKGPREFIX}-${DISTNAME:S/-python//}
 CATEGORIES+=	python
 
@@ -11,12 +12,7 @@ COMMENT=	Python bindings for protobuf
 
 PYSETUPSUBDIR=	python
 
-PYTHON_VERSIONS_INCOMPATIBLE=	34 35 36 # py-gflags
-
-BUILD_DEPENDS+=	${PYPKGPREFIX}-gflags-[0-9]*:../../devel/py-gflags
-BUILD_DEPENDS+=	${PYPKGPREFIX}-google-apputils-[0-9]*:../../devel/py-google-apputils
-BUILD_DEPENDS+=	${PYPKGPREFIX}-dateutil-[0-9]*:../../time/py-dateutil
-BUILD_DEPENDS+=	${PYPKGPREFIX}-pytz-[0-9]*:../../time/py-pytz
+DEPENDS+=	${PYPKGPREFIX}-six>=1.9:../../lang/py-six
 
 EGG_NAME=	protobuf-${PKGVERSION_NOREV}