gbproxy: Replace '.' in counter names with ':'

The '.' is illegal character in counter names, as they are exported
via CTRL interface, where '.' has a special meaning that cannot be
used by strings comprising the variable name.

Change-Id: I93a2e5b6ec66c9edb6e93d95032e788f552af44b
diff --git a/src/gprs/gb_proxy.c b/src/gprs/gb_proxy.c
index 7d21518..447772f 100644
--- a/src/gprs/gb_proxy.c
+++ b/src/gprs/gb_proxy.c
@@ -57,12 +57,12 @@
 	{ "inv-lai",	    "Invalid Location Area Identifier" },
 	{ "inv-rai",	    "Invalid Routing Area Identifier " },
 	{ "inv-nsei",	    "No BVC established for NSEI     " },
-	{ "proto-err.bss",  "BSSGP protocol error      (BSS )" },
-	{ "proto-err.sgsn", "BSSGP protocol error      (SGSN)" },
-	{ "not-supp.bss",   "Feature not supported     (BSS )" },
-	{ "not-supp.sgsn",  "Feature not supported     (SGSN)" },
-	{ "restart.sgsn",   "Restarted RESET procedure (SGSN)" },
-	{ "tx-err.sgsn",    "NS Transmission error     (SGSN)" },
+	{ "proto-err:bss",  "BSSGP protocol error      (BSS )" },
+	{ "proto-err:sgsn", "BSSGP protocol error      (SGSN)" },
+	{ "not-supp:bss",   "Feature not supported     (BSS )" },
+	{ "not-supp:sgsn",  "Feature not supported     (SGSN)" },
+	{ "restart:sgsn",   "Restarted RESET procedure (SGSN)" },
+	{ "tx-err:sgsn",    "NS Transmission error     (SGSN)" },
 	{ "error",          "Other error                     " },
 	{ "mod-peer-err",   "Patch error: no peer            " },
 };