Update sourcing for gcloud completions.

dotfiles/zshrc.d/gcloud.zsh

@@ -2,15 +2,16 @@
 
 GCL=${HOME}/tools/gcloud
 
-if [ ! -d ${GCL} ] ; then
-  return
+if [ -d "${GCL}" ] ; then
+  # Add bin to path
+  export PATH="${PATH}:${GCL}/bin"
+
+  # Load completion
+  source "${GCL}/completion.zsh.inc"
+elif [ -f /usr/share/google-cloud-sdk/completion.zsh.inc ] ; then
+  source /usr/share/google-cloud-sdk/completion.zsh.inc
 fi
 
-# Add bin to path
-export PATH="${PATH}:${GCL}/bin"
-
-# Load completion
-source ${GCL}/completion.zsh.inc
 
 which kubectl 2>/dev/null >&2 && \
   function kubectl() {