cli: fix cluster-deploy

* Updates and installs modules whenever the cluster is redeployed
  in debug mode as new code might come in. Note that it is important
  to do the egg update step before the git submodule step for proper
  debug mode cluster deployment!

* Removes python-install-eggs from cluster-build as the build only
  needs the submodule sources.

reana/reana_dev/cluster.py

@@ -192,8 +192,6 @@ def cluster_build(
     # initalise common submodules
     if mode in ("latest", "debug"):
         cmds.append("reana-dev git-submodule --update")
-    if mode in ("debug"):
-        cmds.append("reana-dev python-install-eggs")
     # build Docker images
     cmd = "reana-dev docker-build"
     if exclude_components:
@@ -319,15 +317,21 @@ def job_mounts_to_config(job_mounts):
     helm_install = "cat <<EOF | helm install reana helm/reana -n {namespace} --create-namespace --wait -f -\n{values}\nEOF".format(
         namespace=namespace, values=values_dict and yaml.dump(values_dict) or "",
     )
-    cmds = [
-        "helm dep update helm/reana",
-        helm_install,
-        "kubectl config set-context --current --namespace={}".format(namespace),
-        os.path.join(
-            get_srcdir("reana"),
-            f"scripts/create-admin-user.sh {instance_name} {admin_email} {admin_password}",
-        ),
-    ]
+    cmds = []
+    if mode in ("debug"):
+        cmds.append("reana-dev python-install-eggs")
+        cmds.append("reana-dev git-submodule --update")
+    cmds.extend(
+        [
+            "helm dep update helm/reana",
+            helm_install,
+            "kubectl config set-context --current --namespace={}".format(namespace),
+            os.path.join(
+                get_srcdir("reana"),
+                f"scripts/create-admin-user.sh {instance_name} {admin_email} {admin_password}",
+            ),
+        ]
+    )
     for cmd in cmds:
         run_command(cmd, "reana")