amend! pull: remove support for --rebase=preserve

pull: remove support for `--rebase=preserve`

In preparation for `git-rebase--preserve-merges.sh` entering its after
life, we remove this (deprecated) option that would still rely on it.

To help users transition who still did not receive the memo about the
deprecation, we offer a helpful error message instead of throwing our
hands in the air and saying that we don't know that option, never heard
of it.

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

rebase.c

@@ -1,5 +1,6 @@
 #include "rebase.h"
 #include "config.h"
+#include "gettext.h"
 
 /*
  * Parses textual value for pull.rebase, branch.<name>.rebase, etc.
@@ -24,6 +25,8 @@ enum rebase_type rebase_parse_value(const char *value)
 		return REBASE_MERGES;
 	else if (!strcmp(value, "interactive") || !strcmp(value, "i"))
 		return REBASE_INTERACTIVE;
+	else if (!strcmp(value, "preserve") || !strcmp(value, "p"))
+		error(_("%s: 'preserve' superseded by 'merges'"), value);
 	/*
 	 * Please update _git_config() in git-completion.bash when you
 	 * add new rebase modes.