rpm: add version to modules-tcl Obsoletes statement

Comply with:
https://fedoraproject.org/wiki/Packaging:Guidelines#Renaming.2FReplacing_Existing_Packages

Thanks to Aurelien Degremont for spotting this.

Fixes #133

contrib/rpm/environment-modules.spec

@@ -42,7 +42,7 @@ Provides:       environment(modules)
 %else
 Provides:       environment-modules
 %endif
-Obsoletes:      modules-tcl
+Obsoletes:      modules-tcl <= 1.923
 
 %description
 The Environment Modules package provides for the dynamic modification of