regen_makefile.sh: Fix TITAN 6.1.0 support

When introducing the rewriting for 6.3.0 we broke the 6.1.0 support.
Now the result should build on Debian with both 6.1.0 and 6.3.0

Change-Id: I263a6abd2d9eb15ce5778ef8dbfcdac2a228b77d
diff --git a/sysinfo/regen_makefile.sh b/sysinfo/regen_makefile.sh
index 1042090..e06b8f5 100755
--- a/sysinfo/regen_makefile.sh
+++ b/sysinfo/regen_makefile.sh
@@ -9,5 +9,5 @@
 sed -i -e 's/CPPFLAGS = -D$(PLATFORM) -I$(TTCN3_DIR)\/include/CPPFLAGS = -D$(PLATFORM) -I$(TTCN3_DIR)\/include -I\/usr\/include\/titan/' Makefile
 
 # for TITAN 6.3.0
-sed -i -e 's/TTCN3_DIR = /TTCN3_DIR = \/usr/' Makefile
+sed -i -e 's/TTCN3_DIR = $/TTCN3_DIR = \/usr/' Makefile
 sed -i -e 's/\/bin\/compiler/\/bin\/ttcn3_compiler/' Makefile