I rolled back to "empathy/natty" only (plus the few dependencies) and that appears to avoid the problem, with the rest of the system fully oneric. Here's what APT said about downgrading to something that works.
Removing nautilus-sendto-empathy ...
Selecting previously deselected package libfolks22. Unpacking libfolks22 (from .../libfolks22_0.4.2-2_i386.deb) ...
Selecting previously deselected package libfolks-telepathy22. Unpacking libfolks-telepathy22 (from .../libfolks-telepathy22_0.4.2-0ubuntu1_i386.deb) ...
Selecting previously deselected package libgcr0. Unpacking libgcr0 (from .../libgcr0_2.92.92.is.2.32.1-0ubuntu2_i386.deb) ...
dpkg: warning: downgrading empathy from 3.1.2.1-1ubuntu1 to 2.34.0-0ubuntu3.1. Preparing to replace empathy 3.1.2.1-1ubuntu1 (using .../empathy_2.34.0-0ubuntu3.1_i386.deb) ... Unpacking replacement empathy ...
dpkg: warning: downgrading empathy-common from 3.1.2.1-1ubuntu1 to 2.34.0-0ubuntu3.1. Preparing to replace empathy-common 3.1.2.1-1ubuntu1 (using .../empathy-common_2.34.0-0ubuntu3.1_all.deb) ...
I rolled back to "empathy/natty" only (plus the few dependencies) and that appears to avoid the problem, with the rest of the system fully oneric. Here's what APT said about downgrading to something that works.
Removing nautilus- sendto- empathy ...
Selecting previously deselected package libfolks22. 0.4.2-2_ i386.deb) ...
Unpacking libfolks22 (from .../libfolks22_
Selecting previously deselected package libfolks- telepathy22. telepathy22 (from .../libfolks- telepathy22_ 0.4.2-0ubuntu1_ i386.deb) ...
Unpacking libfolks-
Selecting previously deselected package libgcr0. 2.92.92. is.2.32. 1-0ubuntu2_ i386.deb) ...
Unpacking libgcr0 (from .../libgcr0_
dpkg: warning: downgrading empathy from 3.1.2.1-1ubuntu1 to 2.34.0-0ubuntu3.1. 2.34.0- 0ubuntu3. 1_i386. deb) ...
Preparing to replace empathy 3.1.2.1-1ubuntu1 (using .../empathy_
Unpacking replacement empathy ...
dpkg: warning: downgrading empathy-common from 3.1.2.1-1ubuntu1 to 2.34.0-0ubuntu3.1. common_ 2.34.0- 0ubuntu3. 1_all.deb) ...
Preparing to replace empathy-common 3.1.2.1-1ubuntu1 (using .../empathy-