Replace `omf.update` with `omf.repo.pull`

- Pull repository from origin unless upstream exist.

pkg/omf/cli/omf.repo.pull.fish

 function omf.repo.pull
+  if test (command git config --get remote.upstream.url)
+    set repository upstream
+  else
+    set repository origin
+  end
+
   set initial_branch (command git symbolic-ref -q --short HEAD); or return $OMF_UNKNOWN_ERR
   set initial_revision (command git rev-parse -q --verify HEAD); or return $OMF_UNKNOWN_ERR
 
@@ -14,8 +20,8 @@ function omf.repo.pull
     command git checkout master --quiet
   end
 
-  # the refspec ensures that 'origin/master' gets updated
-  command git pull --rebase --quiet origin "refs/heads/master:refs/remotes/origin/master"
+  # the refspec ensures that '$repository/master' gets updated
+  command git pull --rebase --quiet $repository "refs/heads/master:refs/remotes/$repository/master"
   if test $status -eq 2 #SIGINT
     command git checkout $initial_branch
     command git reset --hard $initial_revision
@@ -32,4 +38,6 @@ function omf.repo.pull
     echo (omf::em)"Restored your changes:"(omf::off)
     command git status --short --untracked-files
   end
+
+  return 0
 end

pkg/omf/cli/omf.update.fish

-function omf.update
-  set -l repo "upstream"
-  test -z (git config --get remote.upstream.url)
-    and set -l repo "origin"
-
-  if git diff-index --quiet HEAD -- >/dev/null ^&1
-    git pull $repo master >/dev/null ^&1
-  else
-    git stash >/dev/null ^&1
-    if git pull --rebase $repo master >/dev/null ^&1
-      git stash apply >/dev/null ^&1
-    else
-      omf.repo.sync
-    end
-  end
-end

pkg/omf/omf.fish

@@ -125,7 +125,7 @@ function omf -d "Oh My Fish"
     case "u" "up" "upd" "update"
       pushd $OMF_PATH
       echo (omf::em)"Updating Oh My Fish..."(omf::off)
-      if omf.update
+      if omf.repo.pull
         echo (omf::em)"Oh My Fish is up to date."(omf::off)
       else
         echo (omf::err)"Oh My Fish failed to update."(omf::off)