Fix the SONAME.
Fix the SONAME.

We accidentally decreased the SONAME with the 0.6.4 release, so this
adjusts the various easy-to-understand/impossible-to-confuse libtool
numbers.

Closes: bgo#662095

pwithnall/folks,GNOME/folks,renatofilho/folks2,GNOME/folks,renatofilho/folks,renatofilho/folks,renatofilho/folks,pwithnall/folks,renatofilho/folks2,renatofilho/folks2,pwithnall/folks,renatofilho/folks,GNOME/folks,renatofilho/folks2