Grep is confusing enough and does not need to be even harder to use. SVN files are almost always not wanted in a search and just make finding what you want even harder. Luckily you can set a default option.
First jump in to the .bashrc file in your home directory.
nano ~/.bashrc
Then add the options for grep in that file:
GREP_OPTIONS="--exclude=*.svn-base"
export GREP_OPTIONS
Now save and exit the file. Before it will work you need to either restart the session or enter this in the console:
source ~/.bashrc
Wave goodbye to all those pesky svn file.