Unset mod spec on source subcmd if file exists

In case module specification corresponds to a full path name file, unset
parsed module specification on source sub-command. It is done not to
confuse specific character in file path name (like '+') with module
variant specification.

tcl/modspec.tcl

@@ -1490,6 +1490,12 @@ proc getModuleVersSpec {modarg} {
    }
 }
 
+proc unsetModuleVersSpec {modarg} {
+   if {[info exists ::g_moduleVersSpec($modarg)]} {
+      unset ::g_moduleVersSpec($modarg)
+   }
+}
+
 # get module name from module name and version spec if parsed
 proc getModuleNameFromVersSpec {modarg} {
    if {[info exists ::g_moduleVersSpec($modarg)]} {

tcl/subcmd.tcl.in

@@ -814,6 +814,9 @@ proc cmdModuleSource {mode args} {
          set modfile $absfpath
          set modname $absfpath
          set modnamevr $absfpath
+         # unset module specification not to confuse specific char in file
+         # path (like '+') with variant specification
+         unsetModuleVersSpec $mod
          set mod $absfpath
       # if not a path specification, try to resolve a modulefile
       } elseif {![isModuleFullPath $rawarg]} {