Fix incorrect backslash in tde_set_project_version macro

Signed-off-by: Slávek Banko <slavek.banko@axis.cz>
Signed-off-by: Michele Calgaro <michele.calgaro@yahoo.it>
(cherry picked from commit 620a9aa9f9)

modules/TDEVersion.cmake

@@ -26,7 +26,7 @@ macro( tde_set_project_version )
 
   if( EXISTS ${CMAKE_SOURCE_DIR}/.tdescminfo )
     file( STRINGS ${CMAKE_SOURCE_DIR}/.tdescminfo VERSION_STRING REGEX "^Version:.+$" )
-    string( REGEX REPLACE "^Version: (R[0-9]+\.[0-9]+\.[0-9]+.*)$" "\\1" VERSION "${VERSION_STRING}" )
+    string( REGEX REPLACE "^Version: (R[0-9]+\\.[0-9]+\\.[0-9]+.*)$" "\\1" VERSION "${VERSION_STRING}" )
   endif()
 
   if( NOT VERSION )