debian: move .so symlink to -dev package

debian/freeswitch-dev.install

 /usr/include
 /usr/lib/freeswitch/mod/*.la
+/usr/lib/libfreeswitch.so
 /usr/lib/*.a
 /usr/lib/*.la
 /usr/lib/pkgconfig

debian/freeswitch.install

 /usr/bin
-/usr/lib/libfreeswitch.so*
+/usr/lib/libfreeswitch.so.*
 /usr/share/freeswitch/scripts