[2.28 COMMITTED] support_quote_string: Do not use str parameter name

[Florian Weimer <fweimer@redhat.com>]

This avoids a build failure if this identifier is used as a macro
in a test.

(cherry picked from commit 47d8d9a2172f827a8dde7695f415aa6f78a82d0e)

2018-11-28  Florian Weimer  <fweimer@redhat.com>

	* support/support.h (support_quote_string): Do not use str
	parameter name.

diff --git a/support/support.h b/support/support.h
index 4d9f7528a6..4ea92e1c21 100644
--- a/support/support.h
+++ b/support/support.h
@@ -65,10 +65,10 @@ void support_write_file_string (const char *path, const char *contents);
    the result).  */
 char *support_quote_blob (const void *blob, size_t length);
 
-/* Quote the contents of the at STR, in such a way that the result
+/* Quote the contents of the string, in such a way that the result
    string can be included in a C literal (in single/double quotes,
    without putting the quotes into the result).  */
-char *support_quote_string (const char *str);
+char *support_quote_string (const char *);
 
 /* Error-checking wrapper functions which terminate the process on
    error.  */