Fix GCC's -Wuninitialized warnings

Fix the issues found by GCC when the -Wuninitialized flag is specified.

lib/tests/test_disk.c

@@ -34,7 +34,7 @@ main (int argc, char **argv)
 	struct name_list *dummy_mountlist = NULL;
 	struct name_list *temp_name;
 	struct parameter_list *paths = NULL;
-	struct parameter_list *p, *prev, *last;
+	struct parameter_list *p, *prev = NULL, *last = NULL;
 
 	struct mount_entry *dummy_mount_list;
 	struct mount_entry *me;

plugins/check_http.c

@@ -855,18 +855,18 @@ check_http (void)
   char *full_page_new;
   char *buf;
   char *pos;
-  long microsec;
-  double elapsed_time;
-  long microsec_connect;
-  double elapsed_time_connect;
-  long microsec_ssl;
-  double elapsed_time_ssl;
-  long microsec_firstbyte;
-  double elapsed_time_firstbyte;
-  long microsec_headers;
-  double elapsed_time_headers;
-  long microsec_transfer;
-  double elapsed_time_transfer;
+  long microsec = 0L;
+  double elapsed_time = 0.0;
+  long microsec_connect = 0L;
+  double elapsed_time_connect = 0.0;
+  long microsec_ssl = 0L;
+  double elapsed_time_ssl = 0.0;
+  long microsec_firstbyte = 0L;
+  double elapsed_time_firstbyte = 0.0;
+  long microsec_headers = 0L;
+  double elapsed_time_headers = 0.0;
+  long microsec_transfer = 0L;
+  double elapsed_time_transfer = 0.0;
   int page_len = 0;
   int result = STATE_OK;
 

plugins/check_procs.c

@@ -150,7 +150,7 @@ main (int argc, char **argv)
 	int crit = 0; /* number of processes in crit state */
 	int i = 0, j = 0;
 	int result = STATE_UNKNOWN;
-	int ret;
+	int ret = 0;
 	output chld_out, chld_err;
 
 	setlocale (LC_ALL, "");