Use opensfm feature-split-dataset branch

SuperBuild/cmake/External-OpenSfM.cmake

@@ -8,8 +8,8 @@ ExternalProject_Add(${_proj_name}
   STAMP_DIR         ${_SB_BINARY_DIR}/stamp
   #--Download step--------------
   DOWNLOAD_DIR      ${SB_DOWNLOAD_DIR}
-  URL               https://github.com/mapillary/OpenSfM/archive/6536f7cd0bf026db158af96f1508ff8c0616e9be.zip
-  URL_MD5           588e2e6f26837cb053d668401a75200d
+  URL               https://github.com/mapillary/OpenSfM/archive/264fded597c8506669ef413080969d7cb3029797.zip
+  URL_MD5           f941131c3a2506f4db22a11bec0f93f1
   #--Update/Patch step----------
   UPDATE_COMMAND    ""
   #--Configure step-------------
@@ -28,4 +28,3 @@ ExternalProject_Add(${_proj_name}
   LOG_CONFIGURE     OFF
   LOG_BUILD         OFF
 )
-