Merge branch 'sg/prompt-svn-remote-fix' into maint

Bash prompting code to deal with an SVN remote as an upstream
were coded in a way not supported by older Bash versions (3.x).

* sg/prompt-svn-remote-fix:
  bash prompt: don't use '+=' operator in show upstream code path

Author: gitster

contrib/completion/git-prompt.sh

@@ -110,7 +110,7 @@ __git_ps1_show_upstream ()
 			;;
 		svn-remote.*.url)
 			svn_remote[$((${#svn_remote[@]} + 1))]="$value"
-			svn_url_pattern+="\\|$value"
+			svn_url_pattern="$svn_url_pattern\\|$value"
 			upstream=svn+git # default upstream is SVN if available, else git
 			;;
 		esac