shell-completion: restore completion for -p

It was broken since systemd was moved out of /bin.

For zsh it was never there.

Makefile.am

@@ -382,7 +382,6 @@ systemgenerator_PROGRAMS = \
 dist_bashcompletion_DATA = \
 	shell-completion/bash/busctl \
 	shell-completion/bash/journalctl \
-	shell-completion/bash/systemctl \
 	shell-completion/bash/systemd-analyze \
 	shell-completion/bash/systemd-cat \
 	shell-completion/bash/systemd-cgls \
@@ -394,8 +393,10 @@ dist_bashcompletion_DATA = \
 	shell-completion/bash/udevadm \
 	shell-completion/bash/kernel-install
 
+nodist_bashcompletion_DATA = \
+	shell-completion/bash/systemctl
+
 dist_zshcompletion_DATA = \
-	shell-completion/zsh/_systemctl \
 	shell-completion/zsh/_journalctl \
 	shell-completion/zsh/_udevadm \
 	shell-completion/zsh/_kernel-install \
@@ -406,6 +407,17 @@ dist_zshcompletion_DATA = \
 	shell-completion/zsh/_systemd-delta \
 	shell-completion/zsh/_systemd
 
+nodist_zshcompletion_DATA = \
+	shell-completion/zsh/_systemctl
+
+EXTRA_DIST += \
+	shell-completion/bash/systemctl.in \
+	shell-completion/zsh/_systemctl.in
+
+CLEANFILES += \
+	$(nodist_bashcompletion_DATA) \
+	$(nodist_zshcompletion_DATA)
+
 dist_sysctl_DATA = \
 	sysctl.d/50-default.conf
 
@@ -5264,6 +5276,9 @@ src/core/macros.%: src/core/macros.%.in
 src/%.policy.in: src/%.policy.in.in
 	$(SED_PROCESS)
 
+shell-completion/%: shell-completion/%.in
+	$(SED_PROCESS)
+
 %.rules: %.rules.in
 	$(SED_PROCESS)