import-stx: Avoid divide by zero

Fix a divide by zero error seen when the number_of_users
function returns zero.

At issue is that 'users' only counts logins, and can miss
builds running under automation such as jenkins.

Add code to detect potential automation accounts, just
jenkins so far, and to always return a value greater than
zero.

Also adding a few .gitignore entries for files generated by
stx build related scripts.

Closes-bug: 1959606
Signed-off-by: Scott Little <scott.little@windriver.com>
Change-Id: I1369aa159088a17c24cc996be1ef2d36ecdc9cf6

.gitignore

@@ -12,3 +12,7 @@ doc/build/
 
 # Release Notes documentation
 releasenotes/build
+
+# stx init/config/controller files
+stx.conf
+minikube_history.log

import-stx

@@ -41,7 +41,23 @@ if [ ! -f "stx.conf" ]; then
 fi
 
 number_of_users () {
-    users | tr ' ' '\n' | sort --uniq | wc -l
+    local count
+
+    count=$(users | tr ' ' '\n' | sort --uniq | wc -l)
+    
+    # Add in non-login users that might trigger a parallel build
+    # based on a timer, or other trigger.
+    if getent passwd | grep -q jenkins; then
+        count=$((count+1))
+    fi
+
+    # Always return at least one.  i.e. someone is
+    # running this script.
+    if [ $count -le 0 ]; then
+        count=1
+    fi
+
+    echo $count
 }
 
 number_of_cpus () {

stx/lib/stx/.gitignore

@@ -0,0 +1 @@
+__pycache__