git-svn: Use GIT_SSH setting if SVN_SSH is not set

If SVN_SSH is defined, it will be used. Else value in
GIT_SSH is copied to SVN_SSH & then, only on Windows,
the \s are escaped.

On Windows, the shell-variables must be set as follows
    GIT_SSH="C:\Program Files\PuTTY\plink.exe"
    SVN_SSH="C:\\Program Files\\PuTTY\\plink.exe"

See http://code.google.com/p/msysgit/issues/detail?id=305

[ew: fixed indentation to use tabs]

Acked-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Karthik Rajagopalan <karthikr@fastmail.fm>

git-svn.perl

@@ -21,6 +21,15 @@
 $Git::SVN::Ra::_log_window_size = 100;
 $Git::SVN::_minimize_url = 'unset';
 
+if (! exists $ENV{SVN_SSH}) {
+	if (exists $ENV{GIT_SSH}) {
+		$ENV{SVN_SSH} = $ENV{GIT_SSH};
+		if ($^O eq 'msys') {
+			$ENV{SVN_SSH} =~ s/\\/\\\\/g;
+		}
+	}
+}
+
 $Git::SVN::Log::TZ = $ENV{TZ};
 $ENV{TZ} = 'UTC';
 $| = 1; # unbuffer STDOUT