Update insource build error message

Summary

Update the error message shown in case an in-source build is attempted.

Rationale

Remove reference to mercurial scm.

Copyright

The copyright owner is CNES and has signed the ORFEO ToolBox Contributor License Agreement.

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Check before merging:

• All discussions are resolved
• At least 2 votes from core developers, no vote.
• The feature branch is (reasonably) up-to-date with the base branch
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• Copyright owner has signed the ORFEO ToolBox Contributor License Agreement

CMake/PreventInSourceBuilds.cmake

@@ -29,32 +29,13 @@ function(AssureOutOfSourceBuilds)
   if("${srcdir}" STREQUAL "${bindir}")
     message("######################################################")
     message("# OTB should not be configured & built in the OTB source directory")
-    message("# You must run cmake in a build directory.")
-    message("# For example:")
-    message("# mkdir OTB-Sandbox ; cd OTB-Sandbox")
-    message("# hg clone http://hg.orfeo-toolbox.org/OTB # or download & unpack the source tarball")
-    message("# mkdir OTB-Binary ")
-    message("# this will create the following directory structure ")
-    message("#  ")
-    message("# OTB-Sandbox")
-    message("#  +--OTB ")
-    message("#  +--OTB-Binary ")
-    message("#  ")
-    message("# Then you can proceed to configure and build ")
-    message("# by using the following commands ")
-    message("#  ")
-    message("# cd OTB-Binary")
-    message("# ccmake ../OTB")
-    message("# make ")
-    message("#  ")
+    message("# You must run cmake in a build directory outside of the source tree.")
+    message("# See the software guide documentation for example build commands.")
+    message("# ")
     message("# NOTE: Given that you already tried to make an in-source build")
-    message("#       CMake have already created several files & directories")
-    message("#       in your source tree. run 'hg status' to find them and")
-    message("#       remove them by doing:")
-    message("#  ")
-    message("#       cd OTB-Sandbox/OTB")
-    message("#       hg purge ")
-    message("#  ")
+    message("#       CMake has already created several files & directories")
+    message("#       in your source tree. Run 'git status' to find them and")
+    message("#       remove them.")
     message("######################################################")
     message(FATAL_ERROR "Quitting configuration")
   endif()