common: simplify logic to find git

From chroot-git 2.33.1, we always have an executable named git
for other build infrastructure and lints.

Let's remove the shenanegan to find which git to be used, prepend the
path to chroot-git's git into $PATH, and let's the shell call the
correct git for us instead.

.github/workflows/cycles.yml

@@ -33,13 +33,9 @@ jobs:
          common/travis/prepare.sh
       - name: Find cycles and open issues
         run: |
-         if command -v chroot-git >/dev/null 2>&1; then
-             GIT_CMD=$(command -v chroot-git)
-         elif command -v git >/dev/null 2>&1; then
-            GIT_CMD=$(command -v git)
-         fi
+         PATH="/usr/libexec/chroot-git:$PATH"
          # required by git 2.35.2+
-         $GIT_CMD config --global --add safe.directory "$PWD"
+         git config --global --add safe.directory "$PWD"
          common/scripts/xbps-cycles.py | tee cycles
          grep 'Cycle:' cycles | while read -r line; do
              if gh issue list -R "$GITHUB_REPOSITORY" -S "$line" | grep .; then