Build and install libafsauthent.so.2

During the libtool interim, we had been building a .0 but not
installing it.  Prior to the libtoolization of shlibafsauthent, we
had installed a libafsauthent.so.1.1.  The use of libtool is a major
shift, and no one has been explicitly tracking for incompatible
changes in the interim, so it seems prudent to bump the SONAME
for the new stable branch on general principles.

At time of this writing, the libtool rules for updating the
version information is found at:
http://www.gnu.org/software/libtool/manual/html_node/Updating-version-info.html
and
http://www.gnu.org/software/libtool/manual/html_node/Libtool-versioning.html

This lets us consolidate the building of the shared and static libafsrpc
and their installation), as libtool will happily do both for us
at once.

We explicitly do not install the .la files, as our libtool use is
to be kept entirely internal.

Change-Id: I283f9bb74eb9853c268e8642ac1f01741deeae2b
Use convenience library for opr in libafsrpc

If we use a non-pic static library libtool bails; if we use a
dynamic library then we must install that dependency.

Change-Id: I7c92677682c4804e399de17244e3e3f138d83d0d
Use convenience libraries for libafsauthent

We can't use the "regular" versions of these libraries, as they're
shared, and libtool will want to link them shared into the resulting
shared library, which fails since we don't install the helpers yet.
So, use the PIC variants which are already being built.

Change-Id: I8db9a2960c98c37b25e291745b7075b84974b198