Fetch list of all projects lazily

Currently osc <TAB><TAB> takes a long time to complete, which is incredibly
annoying. Only run "osc ls" if it is necessary for proper completion.

dist/osc.complete

@@ -132,7 +132,9 @@ if test -n "$alias" ; then
     command="$command -A $alias"
 fi
 
-if test -s "${projects}" ; then
+update_projects_list ()
+{
+    if test -s "${projects}" ; then
         typeset -i ctime=$(command date -d "$(command stat -c '%z' ${projects})" +'%s')
         typeset -i   now=$(command date -d now +'%s')
         if ((now - ctime > 86400)) ; then
@@ -141,9 +143,10 @@ if test -s "${projects}" ; then
 	        mv -uf $tmp ${projects}
 	    fi
         fi
-else
+    else
         command ${command} ls / >| "${projects}"
-fi
+    fi
+}
 
 projects ()
 {
@@ -159,6 +162,7 @@ projects ()
 	argv[argc++]=$arg
     done
     shift $argc
+    update_projects_list
     cur="$1"
     if test -n "${cur}" ; then
 	list=($(command grep -E "^${cur}" ${projects}))
@@ -273,6 +277,7 @@ targets ()
 
 users ()
 {
+    update_projects_list
     if test -s ${projects} ; then
 	command sed -rn "/^home:$1/{ s/^home:([^:]*):.*/\1/p}" ${projects}|command sort -u
     elif test -s ~/.oscrc; then