mergetool: converting backslashes in kdiff3 path from Windows registry

Backslashes are converted to slashes right after the Windows
registry returned a path. This is needed to avoid problems
with shell expansion.

Signed-off-by: Steffen Prohaska <prohaska@zib.de>

git-mergetool.sh

@@ -323,7 +323,7 @@ if test -z "$merge_tool" ; then
         fi
     fi
     regentry="$(REG QUERY 'HKEY_LOCAL_MACHINE\SOFTWARE\KDiff3\diff-ext' 2>/dev/null)" && {
-        KDIFF3=$(echo "$regentry" | grep diffcommand | cut -f 3)
+        KDIFF3=$(echo "$regentry" | grep diffcommand | cut -f 3 | sed -e 's@\\@/@g')
         KDIFF3SEPARATOR=
         merge_tool_candidates="$merge_tool_candidates kdiff3"
     }