Just tried it and seems to work for me
move the old clone of the bitcoin git to bitcoinold
in the git directory
cd git
mv bitcoin bitcoinold
git clone https://github.com/bitcoin/bitcoin.git
cd bitcoin
git checkout v0.8.6
cd src
make -f makefile.unix
If it still doesnt work post the error.
or you can use the pre-built binaries
from here
http://sourceforge.net/projects/bitcoin/files/Bitcoin/bitcoin-0.8.6/bitcoin-0.8.6-linux.tar.gz/downloadcd
wget http://sourceforge.net/projects/bitcoin/files/Bitcoin/bitcoin-0.8.6/bitcoin-0.8.6-linux.tar.gz/download
tar zvf bitcoin-0.8.6-linux.tar.gz
cd bitcoin-0.8.6-linux/bin/32/
killall -TERM bitcoind
./bitcoind -daemon
check it with ./bitcoind getinfo
and also the logs in your home directory under .bitcoin
to see if its working ok, if so start with options you normally use eg ./bitcoind -blah blah blah
test it out if it works then backup the old bitcoind binary in /usr/local/bin
sudo mv /usr/local/bin/bitcoind /usr/local/bin/bitcoin85
sudo mv ./bitcoind /usr/local/bin/bitcoind
killall -TERM bitcoind
Run it like normal