util: buffer: use VIR_AUTOFREE instead of VIR_FREE for scalar types

By making use of GNU C's cleanup attribute handled by the
VIR_AUTOFREE macro for declaring scalar variables, majority
of the VIR_FREE calls can be dropped, which in turn leads to
getting rid of most of our cleanup sections.
Signed-off-by: NSukrit Bhatnagar <skrtbhtngr@gmail.com>
Reviewed-by: NErik Skultety <eskultet@redhat.com>

src/util/virbuffer.c

@@ -456,7 +456,8 @@ void
 virBufferEscapeString(virBufferPtr buf, const char *format, const char *str)
 {
     int len;
-    char *escaped, *out;
+    VIR_AUTOFREE(char *) escaped = NULL;
+    char *out;
     const char *cur;
     const char forbidden_characters[] = {
         0x01,   0x02,   0x03,   0x04,   0x05,   0x06,   0x07,   0x08,
@@ -533,7 +534,6 @@ virBufferEscapeString(virBufferPtr buf, const char *format, const char *str)
     *out = 0;
 
     virBufferAsprintf(buf, format, escaped);
-    VIR_FREE(escaped);
 }
 
 /**
@@ -612,7 +612,8 @@ virBufferEscape(virBufferPtr buf, char escape, const char *toescape,
                 const char *format, const char *str)
 {
     int len;
-    char *escaped, *out;
+    VIR_AUTOFREE(char *) escaped = NULL;
+    char *out;
     const char *cur;
 
     if ((format == NULL) || (buf == NULL) || (str == NULL))
@@ -644,7 +645,6 @@ virBufferEscape(virBufferPtr buf, char escape, const char *toescape,
     *out = 0;
 
     virBufferAsprintf(buf, format, escaped);
-    VIR_FREE(escaped);
 }
 
 
@@ -690,7 +690,7 @@ virBufferEscapeN(virBufferPtr buf,
 {
     int len;
     size_t i;
-    char *escaped = NULL;
+    VIR_AUTOFREE(char *) escaped = NULL;
     char *out;
     const char *cur;
     virBufferEscapePair escapeItem;
@@ -753,7 +753,6 @@ virBufferEscapeN(virBufferPtr buf,
  cleanup:
     va_end(ap);
     VIR_FREE(escapeList);
-    VIR_FREE(escaped);
 }
 
 
@@ -818,7 +817,8 @@ void
 virBufferEscapeShell(virBufferPtr buf, const char *str)
 {
     int len;
-    char *escaped, *out;
+    VIR_AUTOFREE(char *) escaped = NULL;
+    char *out;
     const char *cur;
 
     if ((buf == NULL) || (str == NULL))
@@ -862,7 +862,6 @@ virBufferEscapeShell(virBufferPtr buf, const char *str)
     *out = 0;
 
     virBufferAdd(buf, escaped, -1);
-    VIR_FREE(escaped);
 }
 
 /**