eclean: dist: make VCS cleaning dependent on --deep

The man page clearly says that without --deep, users can expect eclean-dist
to be conservative in cleaning up, and not consider the VDB, just the repo
state.

Honour that promise by making VCS cleaning dependent on --deep, given it
involves VDB inspection to see what's installed.

Bug: https://bugs.gentoo.org/923369
Signed-off-by: Sam James <[email protected]>

man/eclean.1

@@ -106,6 +106,7 @@ etc.
 Units are: G, M, K and B.
 .TP
 \fB\-\-skip\-vcs\fP                protect VCS sources for live ebuilds not installed
+Only effective with \-\-deep. Without \-\-deep, no VCS cleaning is done.
 .SS "Options for the 'packages' action"
 .TP
 \fB\-i, \-\-ignore\-failure\fP		ignore the failure to locate PKGDIR

pym/gentoolkit/eclean/cli.py

@@ -424,7 +424,7 @@ def optionSwitch(option, opts, action=None):
                 options["unique-use"] = True
             elif o in ("--no-clean-invalid"):
                 options["no-clean-invalid"] = True
-            elif o in ("--skip-vcs"):
+            elif o in ("--skip-vcs") or not options["destructive"]:
                 options["skip-vcs"] = True
             else:
                 return_code = False
@@ -602,11 +602,11 @@ def doAction(action, options, exclude={}, output=None):
             output.einfo("Cleaning " + files_type + "...")
         # do the cleanup, and get size of deleted files
         if options["pretend"]:
-            if options["skip-vcs"]:
+            if options["skip-vcs"] or not options["destructive"]:
                 vcs = {}
             clean_size = cleaner.pretend_clean(clean_me, vcs)
         elif action in ["distfiles"]:
-            if options["skip-vcs"]:
+            if options["skip-vcs"] or not options["destructive"]:
                 vcs = {}
             clean_size = cleaner.clean_dist(clean_me, vcs)
         elif action in ["packages"]: