res_geolocation: Add profile parameter suppress_empty_ca_elements

Added profile parameter "suppress_empty_ca_elements" that
will cause Civic Address elements that are empty to be
suppressed from the outgoing PIDF-LO document.

Fixed a possible SEGV if a sub-parameter value didn't have a
value.

ASTERISK-30177

Change-Id: I924ccc5aa2f45110a3155b22e53dfaf3ef2092dd

configs/samples/geolocation.conf.sample

@@ -170,8 +170,9 @@ location_source = sip1.myserver.net
 Defines the object type.
 type = profile
 
--- profile_precedence (optional) ------------------------------------------
+-- profile_precedence (optional) --------------------------------------
 Sets how to reconcile incoming and configured profiles.
+
 profile_precedence = < prefer_incoming | prefer_config | discard_incoming
     | discard_config >
 
@@ -202,7 +203,9 @@ profile_precedence = prefer_config
 
 -- pidf_element (optional) --------------------------------------------
 PIDF-LO element in which to place the location description.
+
 pidf_element = < tuple | device | person >
+Default: device
 
 If the format is civicAddress or GML, this sets the PIDF element into
 which the location information will be placed.
@@ -217,10 +220,12 @@ Per [RFC5491], "device" is preferred and therefore the default.
 Example:
 pidf_element = tuple
 
--- allow_routing_use (optional) -------------------------------------
+-- allow_routing_use (optional) ---------------------------------------
 Sets whether the "Geolocation-Routing" header is added to outgoing
 requests.
+
 allow_routing_use = < yes | no >
+Default: no
 
 Set to "yes" to indicate that servers later in the path
 can use the location information for routing purposes.  Set to "no"
@@ -253,7 +258,7 @@ floor and room just for this profile
 Example:
 location_info_refinement = floor=20, room=20a2
 
--- location_variables -------------------------------------------------
+-- location_variables (optional) --------------------------------------
 
 If the referenced Location object uses any replacement variables, they
 can be assigned here.  There is no need to define variables that come
@@ -261,6 +266,26 @@ from the channel using this profile.  They get assigned automatically.
 
 location_variables = myfloor=20, myroom=222
 
+-- suppress_empty_ca_elements (optional) ------------------------------
+Sets whether empty values for Civic Address elements should be
+suppressed from the outgoing PIDF-LO document.
+
+suppress_empty_ca_elements = < yes | no >
+Default: no
+
+Setting to "yes" allows you to define a location info template
+with channel variables that may or may not exist.
+
+For example, with:
+location_info_refinement = FLR=${MyFlr}
+suppress_empty_ca_elements = no ; the default
+
+If the MyFlr channel variable weren't set, the outgoing PIDF-LO document
+would have an empty <FLR/> element in it.  If suppress_empty_ca_elements
+were set to "yes", the FLR element would be dropped from the PIDF-LO
+document altogether.
+
+
 -- Profile Example ----------------------------------------------------
 
 [myprofile]