install: print info about skipped packages only in verbose mode

bin/epm-install

@@ -601,7 +601,12 @@ epm_install()
     local names="$(echo $pkg_names | filter_out_installed_packages)"
     local files="$(echo $pkg_files | filter_out_installed_packages)"
 
-    [ -z "$files$names" ] && info "Skip empty install list" && return 22
+    # can be empty only after skip installed
+    if [ -z "$files$names" ] ; then
+        # TODO: assert $skip_installed
+        [ -n "$verbose" ] && info "Skip empty install list"
+        return 22
+    fi
 
     if [ -z "$files" ] && [ -z "$direct" ] ; then
         # it is useful for first time running