build: shut up automake warnings

build: shut up automake warnings

I'm tired of seeing screenfuls of messages like these when using
automake 1.13 (Fedora 19):

configure.ac:2121: warning: The 'AM_PROG_MKDIR_P' macro is deprecated, and its use is discouraged.
configure.ac:2121: You should use the Autoconf-provided 'AC_PROG_MKDIR_P' macro instead,
configure.ac:2121: and use '$(MKDIR_P)' instead of '$(mkdir_p)'in your Makefile.am files.
daemon/Makefile.am:19: warning: 'INCLUDES' is the old name for 'AM_CPPFLAGS' (or '*_CPPFLAGS')

seeing as how we MUST use those constructs for the benefit of
automake 1.9 (RHEL 5).  Conversely, RHEL 5 automake complained:

aclocal:configure.ac:36: warning: macro `AM_SILENT_RULES' not found in library

Obviously, I tested this patch on both Fedora 19 and RHEL 5.

* configure.ac (AM_INIT_AUTOMAKE): Avoid obsoletion warnings.
(AM_SILENT_RULES): Avoid unknown macro warning.

Signed-off-by: Eric Blake <eblake@redhat.com>