Don't assume git version has just three numbers

Author: polytypic

.travis.yml

@@ -17,7 +17,7 @@ git:
 
 before_install:
   - export -f travis_nanoseconds travis_time_start travis_time_finish
-  - export GIT_DEPTH=$(if [ 002021000 -le $(git --version | sed -e 's#[^0-9.]*##g' -e 's#\([0-9]*\)#00\1#g' -e 's#[0-9]*\([0-9]\{3\}\)\.*#\1#g') ]; then echo '--depth 1'; fi)
+  - export GIT_DEPTH=$(if [ 002021000 -le $(git --version | sed -e 's#^[^0-9]*\([0-9]*\)\.\([0-9]*\)\.\([0-9]*\).*$#00\1.00\2.00\3#g' -e 's#[0-9]*\([0-9]\{3\}\)\.*#\1#g') ]; then echo '--depth 1'; fi)
 
 script:
   - if ! [ -x .cppsm/travis-ci ]; then git submodule --quiet update --init --no-recommend-shallow $GIT_DEPTH .cppsm; fi