After compiling Bitcoin Core following their guidelines I get a "dirty" version as seen in the screenshot below.

git clone https://github.com/bitcoin/bitcoin.git
cd bitcoin
sudo git checkout 0.15
sudo ./autogen.sh
sudo ./configure LDFLAGS="-L/root/bitcoin/db4/lib/" CPPFLAGS="-I/root/bitcoin/db4/include/"
sudo make -s -j5
sudo make install

I also am unable to get the node listed on https://bitnodes.21.co and I presume it's because of this? Using the normal Bitcoin Core node bitcoin.org has already compiled works fine in that regard.

Why is it doing this and how can I compile a normal version? It does the same if I compile 0.14