Apply patch to wrong folder displays empty error

[Morten Madsen]

I accidentally tried to apply a patch to a folder where the patch was not created from. I got an empty error window with TortoiseMerge in the title.

Reproduction:
1. I made a change at
rep/directory/subdirectory1/somefile1.txt

2. Created a patch at
rep/directory/

3. Tried to apply the patch to
rep/

Windows 10 x64
TortoiseSVN 1.9.7, Build 27907 - 64 Bit , 2017/08/08 19:34:38
Subversion 1.9.7, -release
apr 1.5.2
apr-util 1.5.4
serf 1.3.9
OpenSSL 1.0.2l 25 May 2017
zlib 1.2.8
SQLite 3.14.1