doc: Add a trailing -- to the git command in FILE_VERSION_FILTER

This makes sure no path will be interpreted as a revision.

doc/Doxyfile.in

@@ -586,7 +586,7 @@ SHOW_NAMESPACES        = YES
 # provided by doxygen. Whatever the program writes to standard output
 # is used as the file version. See the manual for examples.
 
-FILE_VERSION_FILTER    = "git log -n 1 --pretty=format:%h"
+FILE_VERSION_FILTER    = "git log -n 1 --pretty=format:%h --"
 
 # The LAYOUT_FILE tag can be used to specify a layout file which will be parsed
 # by doxygen. The layout file controls the global structure of the generated