plugin: use namespace prefix osmo_*

Summary of changes:

s/plugin_load_all/osmo_plugin_load_all/g
diff --git a/src/gsm/gprs_cipher_core.c b/src/gsm/gprs_cipher_core.c
index 0ff85e2..7884be0 100644
--- a/src/gsm/gprs_cipher_core.c
+++ b/src/gsm/gprs_cipher_core.c
@@ -53,7 +53,7 @@
 int gprs_cipher_load(const char *path)
 {
 	/* load all plugins available from path */
-	return plugin_load_all(path);
+	return osmo_plugin_load_all(path);
 }
 
 /* function to be called by core code */
diff --git a/src/plugin.c b/src/plugin.c
index 4d9fd31..998bca3 100644
--- a/src/plugin.c
+++ b/src/plugin.c
@@ -32,7 +32,7 @@
 
 #include <osmocom/core/plugin.h>
 
-int plugin_load_all(const char *directory)
+int osmo_plugin_load_all(const char *directory)
 {
 	unsigned int num = 0;
 	char fname[PATH_MAX];
@@ -55,7 +55,7 @@
 	return num;
 }
 #else
-int plugin_load_all(const char *directory)
+int osmo_plugin_load_all(const char *directory)
 {
 	return 0;
 }