CircleCI: Run git log with --no-pager option

Otherwise, if commit message is long and `--More--` displayed,
then the build will hang and eventually terminate with:

    Too long with no output (exceeded 10m0s): context deadline exceeded

.ci/get-boost.sh

@@ -87,7 +87,7 @@ git submodule --quiet update --init $GIT_SUBMODULE_OPTS \
 
 if [ -d ./.git ]; then
     echo "get-boost: git log --stat -1"
-    git log -1
+    git --no-pager log --stat -1
 fi
 
 echo "get-boost: Deleting $PWD/libs/gil cloned with Boost superproject"
@@ -100,7 +100,7 @@ if [ -d libs/gil/.git ]; then
     current_pwd=`pwd`
     cd libs/gil
     echo "get-boost: git log --stat -1"
-    git log -1
+    git --no-pager log --stat -1
     cd $current_pwd
 fi